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December 9, 2016
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March 23, 2001
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PDF icon CIA-RDP78S05452A000100040010-2.pdf3.18 MB
Approved For Release' 200,140,7,f% II introduction THE BIG PLUS applications SELECTIVE CALLING EQUIPMENT APPLICATIONS REMOTE CONTROL functions BASIC FUNCTIONS basic operation ELECTRICAL PULSES STUNT BOX LOCATION FUNCTION MECHANISM (basic components) FUNCTION MECHANISM (cycle of operation) components detailed FUNCTION BARS PAWLS and LEVERS COMPLETE STUNT BOX detailed operation FORKS, SLIDES, SWITCHES (latching-unlatching) SELECTIVE CALLING (terminology) SELECTIVE CALLING (in action) ? 1959 by TELETYPE CORPORATION Approved For Rele The age of commercial jet air travel is here. It has brought with it the need for even faster, more efficient nation- wide communication of weather data, flight plans, and routine message traffic., From the local level to central control, Teletype supplies equipment that helps meet this need. Automatic polling of outlying stations includes the utilization of the "stunt box" in assimilating and disseminating weather information and other air traffic data faster than ever before. r,'PAGE PUNTER Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 introduction THE BIG PLUS what it is, what it does ... This brochure is the story of "more value" . . . a "BIG PLUS" feature of Teletype Model 28 equip- ment. It is the factual story of a "futuristic," component assembly called the STUNT BOX. One of the most outstanding characteristics of 100 word-per-minute, Teletype Model 28 equip- ment is its versatility ... achieved to a great degree by this stunt box. Contained in a lightweight aluminum housing within the typing unit, the stunt box is 9A " long, 4Y " wide and 2% " high. Compactly arranged, it is the key to an entirely new control concept in the field of record communications. How does the stunt box affect page printer operation? Early teletypewriters had two shift positions. One was the "Letters" case, which allowed the operator to use 32 combinations of the conven- tional, 5-level, Baudot, telegraphic code for printing 26 letters of the alphabet and performing 6 related functions. The other was the "Figures" case, or shift position, for printing numbers, symbols and performing functions-also utilizing the same 32 code combinations. Early equipment, however, was limited in scope of operation because among other things, when additional special non-printing functions were required, it was often necessary to sacrifice printed characters. To overcome this inadequacy, the Teletype Model 28 page printer stunt box provides a "BIG PLUS" third shift feature, which enables the 32 combinations of the "Letters-Figures" shift con- ditions to be again reused to perform special non- printing functions, without ever sacrificing a single printed character. Also with early equipment, only one character could be assigned to perform a single function. With the Model 28 stunt box, a single character into a code sequence to perform a single function. These aids to printer operation, while im- portant, are only a small part of the capabilities of this unique assembly. Serving as an automatic control device for local and remote operations, responding to keyboard or line signals, the stunt box is actually a built-in sequential selector. Literally, this means the stunt box serves as a memory storage medium, with a mechanism for translating discrete electrical pulses into mechani- cal motion. This motion, in turn, further initiates mechanical or electrical actions to perform desired operations. The remote control applications of the Model 28 stunt box alone are becoming so popular that a special self-contained, sequential selector unit has been perfected just for this purpose. Major use of this dynamic unit is concerned with "selective calling" and "integrated data process- ing" applications. In any situation requiring re- mote control, the Teletype Model 28 typing unit with its stunt box can perform tasks usually as- signed to costly, more complex, larger equipment. Utilizing the stunt box, operational procedures in both large and small communication networks can be simplified, equipment bulk can be reduced How the stunt box got its name In the early days of printing telegraphy, "stunts" was the term applied to nonprinting functions. These functions were actuated by function or "stunt" bars in the function assembly of printing telegraph equip- ment. Early use of the term day designation of the function assembly as a "stunt box." What can the stunt box do? New uses have been found for this flexible, ver- satile unit faster than we've been able to list them. From present indications, the variety of applica- tions for this control mechanism will continue to be limitless. Basically, the stunt box will perform the follow- ing operations: 1 Mechanically initiate internal functions within the typing unit of the page printer set. 2 Electrically control functions within the page printer set. 3 Electrically control external equipment. What does this mean? Let's consider a hypothetical situation: Suppose you were a midwesterner who liked to drink hot coffee in the morning just after arrival at your office. You could arrange to have your New York operator (who, due to time differences would begin an hour earlier than you) send a signal at a specified time daily. This signal would cause the programmed stunt box in your Teletype printer to operate a switch controlling a coffee percolator. Upon arrival at the office, you could begin your business day with hot coffee, cup in hand. We mention this seemingly whimsical example only to point out the fact that ... utilizing the stunt box ... anyone can do anything from turning on a coffee percolator at a remote location, to calling in an entire network of stations from coast can be used or several charactApprovecd? Or' elease /07% &eed I~a' '3 4 1 0 116- 1?ast' application proved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 SELECTIVE CALLING ... inter plant or intra-plant INTER-PLANT The most popular application of the stunt box in communications and data processing is its use as a sequential selector for message directing. Consider a nationwide inter-plant network consisting of Teletype Model 28 equipment. Circuits for this system can be established through the stunt box in a variety of ways. One city can call all other cities simultaneously ... individually ... or in groups of 2, 3, 4, etc. A detailed description of how this is accomplished is found in a special section of this brochure devoted to SELECTIVE CALLING functional operations. (See pages 16 and 17.) ,,TIZOIT YORK INEW ORLEANS INTRA-PLANT The same procedure can be applied to an intra-plant operation with page printers or automatic send-receive sets located in spe- cific departments, such as: A The principal advantage of these systems is that message traffic can be selectively directed only to those printers actually concerned with the information being transmitted. Printers in the system that are not called in are always "alert", their stunt boxes continually "riding- the-line," waiting for specific information to be directed to them. When the stunt box recognizes a control signal directed to its printer, a "lightning" chain of events begins, allowing the selected printer to start operations. RECEIVING 19 ACCOUNTING Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 applications EQUIPMENT APPLICATIONS ... all involve stunt box use To illustrate an example of selective calling in actual business practice, let us consider an integrated data processing system. An operator at the keyboard of a Teletype Model 28 page printer or automatic send-receive set, completely fills out a SALES order. As she enters information onto the form, the stunt box auto- matically and selectively directs pertinent information to those specific departments concerned with the particular information being entered. For example ... every department would get the order number, while cost information would be received only by ACCOUNTING, BILLING and MANAGEMENT. In conjunction with IDP applications ... when a Teletype printer is equipped with a sprocket feed platen for multi-carbon forms ... the stunt box activates the operation of such required functions as horizontal tabulator, vertical tabulator and form feed-out. Other equipment applications include automatic switching, code conversion (sequential signals to multi-wire output), digital tele- metering, control of mechanical production in the "automatic factory," error checking and a variety of special uses. A typical example of a special use is an application where the stunt box is used to "trigger" an answer back unit that sends a message veri- fication character to the sending unit. POPULAR APPLICATIONS The selective capabilities of the stunt box as well as all of its other operations can be tailored to your individual needs. You have only to define what you would like it to ac- complish . . . Teletype engineers will be pleased to show you how the stunt box can fulfill your requirements. Approved For Release 20 Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 applications REMOTE CONTROL ... controls electrical equipment anywhere OPERATOR AT KEYBOARD CONTROLS TELETYPE MODEL 28 TAPE READER In addition to its use in selective calling and integrated data processing, another major application of the stunt box is con- trolling auxiliary apparatus. In this category is the control of Teletype tape punches, readers and business machines of all kinds. Stunt box action can tell one machine to record on tape, another to record on a form, and others to "listen" but not record. TELETYPE MODEL 28 MISCELLANEOUS TAPE PUNCH EQUIPMENT Unlimited applications of the stunt box are possible through its ability to close and open electrical contacts for equipment such as alarms, signal lamps, signal bells, and motor controls in remote locations. Illuminate an area, increase pumping pressure, start a computer ... all these, and many more, actions can be accomplished at the same time, on the same circuit-with each machine responding only to its own instruction through stunt box control. In conjunction with remote control as related to various busi- ness machines ... through stunt box use, sequential signal input to the printer can be converted to multi-wire output for use by auxiliary equipment. An enormous field of application is opened by combining systems when this feature is employed with available commercial data processing equipment. When considering remote control equipment it should be remem- bered that the Teletype Model 28 stunt box can start or stop any electrical operation controlled by a switch. The stunt box is considered the "robot brain" of the units shown here. Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 BASIC FUNCTIONS... make possible a variety of applications Physically surrounded by the framework of its aluminum housing, the stunt box is provided with forty two code slots. Each of these slots will accommodate a function mechanism that is designed to perform a specific function. As stated earlier, the stunt box will perform three basic func- tion operations-internal mechanical ... internal electrical ... and external electrical. These operations can be accomplished individually or simultaneously, depending on how the stunt box function mechanism has been coded, "set up," or programmed. Normally, six of the stunt box's code slots are assigned to standard nontyping printer functions ... they are: 1 Letters Shift 4 Line Feed 2 Figures Shift 5 Blank 3 Carriage Return 6 Space Suppression for Line Feed Besides the six basic essential nonprinting functions, a number of additional functions may be introduced. With modifications to the basic function mechanisms, and with additional parts placed in the remaining open code slots, the following functions may be performed: 1 Automatic Carriage Return and Line Feed 2 Unshift on Space 3 On-line Backspace 4 Horizontal Tabulation 5 Keyboard Lock functions 6 On-line, Reverse Line Feed 7 Form Feed-out 8 Signal Bell Contact 9 Busy Light Contact 10 Motor Stop Contact 11 Vertical Tabulation The necessary parts can be supplied to equip your Teletype units for handling any desired additional functions. To increase versatility, field conversions may be made in which completely different stunt box arrangements are interchanged. The Sequential Selector The popularity of utilizing the stunt box as a control unit even where the page printer is not required, brought about the development of the Teletype Model 28 sequential selector. This unit is similar to the page printer typing unit except that the printing and paper handling mechanisms have been removed. It is exclusively used in remote control operation. sequential selector. This unit is activated by incoming sequential signals. Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 basic operation Pulses originate at keyboard ELECTRICAL PULSES ... how a message is sent electrically Pulses received and converted to tape intelligence Teletypewriter equipment is unique in that it permits the instantaneous delivery of printed messages regardless of the distance they must travel. This is of course possible because these messages are transmitted in the form of electrical pulses-which travel with the speed of light. When the contact in the signal line is closed, current flows and the line is said to be "marking." A MARKING PULSE is gen- erated when the contact is held closed for a fixed length of time. 0 0 000. 00 0 000 00'' 0 0 0 0 0 0 0 0 00 0 ?0 a0 2 3 SPACE SPACE 0 0000 00 0 0 0 00 Mai In addition to the code pulses, (which transmit the message) each combination is preceded by a start pulse (always spacing) and followed by a stop pulse (always marking) for synchronization. 0 0 0 0 0 00 . 00 000 ? ? ? ?' ? ? ? ? ? 0,0 ? ? 0? 0 000 0 0 0 0 0 0 00 Approvg8"ftFs MLgt6E R i'9$6 P -RDP78S05452A000100040010-2 One of a Variety of Teletype Equipment Coding Arrangements A pulse is simply a unit of time during which the flow of current in the signal line is either permitted to continue -or is interrupted-by the operation of a contact. Messages originate with keyboard action or transmis- sion from a tape reader. Mechanical actions are converted into electrical pulses for transmission over telephone or telegraph lines and through radio facilities. IR When the contact is opened, no current can flow and the line is said to be "spacing." A SPACING PULSE is generated when the contact is held open for a fixed length of time. 5 SPACE Each character in a typical code consists of five Using the letter "D" as an example, pulses one and electrical pulses which may be either marking or four are marking while pulses two, three, and five spacing. Red indicates a marking pulse, white a are spacing. spacing pulse. Illustrated at left is ,a typical coding arrangement as used in punched paper tape. "FIGURES" refers to the character indicated on the upper portion of a Model 28 key top. "LETTERS" refers to the character indicated on the lower portion of the key top. RED DOTS indicate marking pulse transmission. WHITE DOTS indicate spacing pulse transmission. (Black dots are feed holes). Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 basic operation STUNT BOX LOCATION ... relationship to typing unit code bars We already know that the seemingly magic-like stunt box is a compact control mechanism measuring 9% 'by 4Y2 'by 2% " over-all. Now let us relate the stunt box to the position it occu- Rear view of Teletype Model 28 typing unit with area occupied by stunt box shown in red. Actual Operation With an understanding of the relationship of the stunt box to the code bars we can proceed with the mechanics of actual operation. All operation begins with the receipt of a signal . i.e., series of pulses-"marking," or-"spac- ing." This signal is received by the selector mecha- nism of the typing unit. It is converted into mechanical action within the typing unit. Link- ages activated by this action, position five equally notched bars, called code bars, to the left if the pulse is marking or right if the pulse is spacing. pies when performing all of its "magicianly" tasks. The stunt box extends across the full width of the Teletype Model 28 typing unit of the page printer, automatic send-receive set and sequential selector. Rear view of typing unit with stunt box re- moved. Code bar assembly is shown in green. Actually there are nine code bars, five for intel- ligence others for functions. From top to bottom they are identified in the illustration at right. The rear portions of the code bars are identically notched. Because some code bars will be posi- tioned to the left and others to the right, the vertical alignment of both projections and slots will present a staggered pattern. This over-all pat- tern changes with the receipt of each variation in signals received. Let us now determine how this action affects actual stunt box operation. Partial section of typing unit in perspective shows stunt box in red and code bars in green. The two fork-like projections on top of the stunt box are called "shift forks." Shift forks position Suppression, Zero, and Figures-Letters Shift code bars through studs. .a-- COMMON f- ZERO FIGURES-LETTERS SHIFT Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 basic operation FUNCTION MECHANISM... basic components As previously stated, the stunt box has forty-two code slots. They are marked at 10-20-30 and 40 slot intervals as viewed from the rear. Consider one opening or code slot in the stunt box ... let's see how its function mechanism is affected by the code bars. The projections at the front of the function bar are called tines. The illustration below shows a partial top view of the code bars and two func- tion bars. Viewed from the side, in a cut-away drawing of the stunt box code slot ... the function bar, pawl and lever are related to each other as follows: TOP VIEW Selected function bar (Completely forward) TOP VIEW Unselected function bar (Forward motion blocked) The motion of the function bar is initially forward and then to the rear. If code bar projections do not block function bar tines, the function bar moves completely forward. If code bar projections block function bar tines, forward movement is stopped. A function bar front end as viewed from the rear of the code bars will show tines angled to Stripper Blade To this view we shall add the STRIPPER BLADE which extends along the rear length of the stunt box. The motion of the stripper blade is first down and then up. Function Reset Bail To this view we shall also add the FUNC- TION RESET BAIL which moves forward and to the rear, mak- ing contact with the lowest forward projec- tion of the function bar. Movements of the stripper blade and the function reset bail are controlled by linkages to the main shaft of the typing unit. Their complete cycle of operation is based on one revolution of the main shaft. This view illustrates atypical stunt box mechanism in an engaged position. We know that the code bars are positioned depending on the signal received. Now let us follow the simple operation of the stunt box mechanism from a disengaged position to an engaged condition and back in to a position of rest. Approved For Release 2001/07/16: CIA-RDP78SO5452A000100040010-2ga are called marking tines, those to the right are called spacing tines. A fully loaded or "universal" function bar con- tains sixteen tines (eight "marking" and eight "spacing"). Tines can easily be removed from the universal function bar so that it will operate on any desired code. This is a Function Pawl The function pawl is engaged by the rear upper projection of the function bar. This is a Function Lever The function lever is engaged by the function pawl. This view illustrates a typical function box mechanism in a disengaged position. FUNCTION MECHANISM ... cycle of operation 1 The function reset bail holds the function bar in the disengaged position. 2 As the typing unit main shaft revolves, pres- sure from the function reset bail is released from the lower projection of the function bar. function 3 The "spring-loaded" .. begins to move to the front. 4 If the code combination in the typing unit code bars is such that the tines of the function bar are not blocked by the code bar projec- tions, then the function bar will move far enough forward to let the function pawl fall into engagement. 5 As the function bar is returned to the rear the backward movement of the reset bail, t function pawl also is carried to the rear. I 6 The function pawl engages the function [ever which pivots with its top portion moving to the rear. IT IS THIS MOTION OF THE basic operation FUNCTION LEVER THAT INITIATES THE OPERATION OF A FUNCTION. 7 The function pawl in its most rearward posi- tion, still in the engaged condition, is returned to the disengaged position by the upward movement of the stripper blade. 8 When the function pawl is raised, its spring pulls forward. I he function pawl's Fo-wer pro- jection then rests on the upper rear projection of the function bar. CYCLE OF OPERATION illustrated Reviewed in graphic form the operation cycle is illustrated below: A Function bar moves for- ward . . . tines feel for opening in code bars. B If function bar tines find opening, function bar moves completely forward . . . function bar upper rear projec- tion is engaged by fall- ing function pawl. C Function reset bail forces function bar and engaged pawl to rear. Pawl engages function lever ... function lever initiates operation of function. D Stripper blade removes pawl from function bar. E Function mechanism returned to disengaged position. Basically this cycle describes the complete operation of the function mechanism in one code slot. The following pages go into detail regarding each part of the mechanism with information as to how numerous stunt box functions are performed. ILI Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 Function bars are literally the "passkeys" to the performance of functions. In their forward motion into the "lock-like" code bars-they search for an opening. Like keys ... function bar projections vary ... and they vary in several ways. The number of tines and the way they are angled ... left, for marking and right, for spacing usually varies from one function bar to the next. Shown below in front views are function bars with tine arrange- ments corresponding to the 5-level signal characters that will allow these function bars to move completely forward. Coding Function Bars As indicated in this diagram ... by snap- ping off tines, "universal" function bars can be coded for any one of the code characters. components detailed FUNCTION BARS ... how they are coded Universal Function Bar SUPPRESSION 4th. PULSE 1st. PULSE 5th. PULSE 2nd. PULSE 3rd. PULSE ZERO FIGS.-LTRS. Illustrated above is a side view of the fully loaded bar called the "universal" function bar. At left, is the front view of this bar with tines identified as to the level of typing unit code bars they contact. Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 Approved For Release 2001/07/16 : CIA-RDP78S05452A000100040010-2 components detailed FUNCTION PAWLS and LEVERS... -,A!,hat they are, what they do Function Levers The motion of the func- tion levers initiates the actual operation of a function. Projections of the function lever move slides, bails, operate electrical contacts, block other levers and engage latches. Studs and bails can be mounted on cer- tain lever projections. As a result of these actions, all of the opera- tions of the stunt box can be performed. Illustrated at right are twelve function levers. Letters identify various projections. The purpose of each projection is ex- plained in the copy block below the levers. Function Pawls The function pawl is the simplest of the principal parts of the function mechanism. There are three pawls available. Standard Pawl Special Pawl Accessory Pawl A Used to operate a shift slide or an electrical contact. B Used to operate an electrical contact which is installed in line with the function lever and, in addition, an electrical contact installed in line with the next lower numbered slot. C This extension is for use in the next lower numbered slot adjacent to the slot in which a function lever with extension "B" is used. D Used to block the operation of the function bar in the adjacent higher numbered slot. E Used to block the operation of the function bar in the same slot. F Used if the function lever is to be latched in the operated position. G Used to operate a slide arm associated with the operation of such functions as carriage return, line feed, horizontal tabulation, page feed-out, etc. I ?.._= H H __G J This extension is similar to extension I, except that it is used whe' spacing is not suppressed. The curve in the extension permits operation of the function lever without operating the space suppres- sion bail. K This extension is required when the function lever has extension E. A function lever with extension E can be operated only by the release bail shaft (or by a stud in extension I or J of a function lever in an adjacent slot). engaging the extension K. Because stunt box applications are ever increasing, modifications of the levers shown here and additions to the total number may occur. The special pawl operates its own function lever and the lever in the adjacent higher numbered stunt box code slot. When this special pawl is used, an accessory pawl must be used in the higher numbered slot. Approved For Release 2001/07/16 : CIA-RDP78S05452A000100040010-2 Approved For Release 2001/07/16 : CIA-RDP78S05452A000100040010-2 components detailed THE COMPLETE STUNT BOX ... additional components detailed As illustrated, the spring plate provides an anchor for one end of the function lever spring. Function Latches If it is desirable to keep a function lever in the operated position . . . a function latch is substi- tuted for the spring plate. In addition to providing an anchor for one end of the function lever spring-the function latch will engage a function lever with a latch exten- sion, and hold the lever in the operated position until released by the stripper blade during the next cycle of operation. The function lever can be kept in the latched position for any required length of time. Three additional methods of unlatching are available. The first method is to have a single stud on an adjacent lever release the latch when required. A lever with a double stud will operate latches in adjacent slots on both sides. A latch release bail shaft is also available for unlatching. Function lever latch release bail shafts span code slots at varying intervals from 4 to 35 slots. Shaft lengths extending across the following con- secutive code slots are available: 4, 6, 8, 9, 12, 14, 17, 22, 25, 27, 32 and 35. Approved For Release 2001/07/16 : CIA-RDP78S05452A000100040010-2 Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 detailed operation FORKS, SLIDES, SWITCHES ... also ... latching... unlatching Cutaway of Stunt Box Three Function Mechanisms Detailed (Note: Not in true scale. Projections and distances are exaggerated for greater clarity.) 0 Shift Fork The shift fork engages the vertical posts that move the zero, Figures-Letters shift and suppression code bars from the marking to the spacing position. Shift Slide Shift slides operate the shift fork. Shift slides are operated by function levers. From one to six function levers can operate a single slide. Illustrated at left are typical shift slides. Switches Switch blocks for mounting on function lever guide plate are available. Each block can be equipped with up to four arms for "make", "break" or transfer contact operation. With stunt box pro- gramming these arms can be set for momentary operation of the contacts, for one cycle of opera- tion, or for a sustained condition of closed or open contacts. A. Shows "make" or contact switch arm with rear- ward action of top of function lever. B. Shows "break" or no contact switch arm with rearward action of top of function lever. LATCHING - UNLATCHING... key to sequential selection COLOR CODE ? FIRST FUNCTION 40 SECOND FUNCTION MECHANISM THIRD FUNCTION MECHANISM Let us now follow the sequential operation of the function mechanisms in a stunt box that has been coded to perform a function on the receipt of the third character in a sequence of three characters. The first character of the three character sequence is received by the selector, proc- essed by the typing unit linkages and code bars, and then interpreted by the first function bar. The function pawl of the selected (first) function bar pivots the first function lever, around its pivot point. This movement re- moves the blocking projection of the first function lever that has been preventing the forward motion of the second (or adjacent) function bar. The first function lever is latched up in its operated position by a latch lever. The stripper blade rises to disengage the first function pawl from the first function bar. The second function bar is selected by receipt of the second character of the select- ing sequence, initiating a similar chain of events. While the second function bar is being selected, the stripper blade descends and strikes the first latch lever arm which releases the first function lever. Should a character be interposed between the first and second character of the selecting se- quence, the projection blocking forward movement of the second function bar will be restored, and will prevent selection of this function bar by the second character of the selecting sequence. While the second function lever is latched in the operated position, the third consecu- tive character of the selecting sequence will position the code bars to allow operation of the third function bar, which through its function lever activates a switch, slide, lever, bail, etc., to perform the desired function. Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 I detailed op~r~ ion d For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 SELECTIVE CALLING... terminology Teletype Model 28 Keyboard consists of four rows of keys; top row of "red" func- tion keys . . . and three rows of "green" printing character keys. Top portion of key top indicates character printed in "FIGURES." Typical CHARACTER Key Tops Bottom portion of key top indicates character printed in "LETTERS." Illustrated at right is a Teletype Model 28 Automatic Send-Receive Set. Keyboard is identical to Teletype Model 28 Page Printer. introduction to selective calling Before illustrating and describing a typical selec- tive calling operation in detail, we should first be acquainted with some general information about 2 the page printer and what it will do. Specifically the Teletype Model 28 page printer will perform in three basic operational areas. I The first of these areas is referred to as "Letters." In this condition the printer types alphabetical characters and performs func- tions as indicated on the lower portion of the printer's green keytops. When the typebox shifts to "Figures" the second area, symbols and numerical char- acters as indicated on the upper portion of the keytops will be printed. In the third area, "Select-Non Print," direct printing is suppressed while the signal selector and stunt box remain active. The printer is always awake, its stunt box always riding the line, waiting for information to be directed to it. The detailed description of selective calling at right, applies to a method that one specific cus- tomer has elected to use. This system provides for the assignment of an identification code to every printer on the circuit. This code can be made up of any character or sequence of characters. Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 Approved For Release 2001/07/16 : CIA-RDP78S05452A000100040010-2 detailed operation SELECTIVE CALLING ... sequential selection in action We already know that various function levers, pawls and bars along with other parts of the func- tion mechanism can perform functions, block func- tions and control time intervals of make or break electrical contacts. With this knowledge, we can in detail show how the systems illustrated on page four can operate. Identification Codes, or call directing characters (CDC's), are assigned to each printer in the sys- tem. The following four basic steps are in this plan: 1 Conditioning Code-With the transmission of a sequence conditioning code such as "Figs-H-Ltrs," the printers will respond to the three characters in the following manner: The "Figs" function mechanism unlatches the "H" function mechanism. The "H" mechanism will operate if selected. The "H" function lever activates the latch release bail which trips off function levers with shift forks that return the zero and suppression code bars from the spacing to the marking position. This means all of the printers on the circuit are now in what is called the SELECT-NON PRINT condition. The "Ctrs" signal is used to compensate for mechanical time lag. 2 Call Directing Code-With the reception of the identification code or call directing character or characters (CDC's) that are assigned to specific printers in the system -selected stunt box function mechanisms move the suppression code bar to the spac- ing side, unblocking the type box clutch of the typing unit. All of the printers that have been selected are now in the SELECT PRINT condition. These printers are in the "Let- ters" print position and they are now ready to receive and type a message. (In calling printers, when more than one character is used as a CDC, the function lever of the first character is latched up to permit the 2nd function lever to operate. See "LATCHING ... UNLATCHING," page 15.) 3 End of Address-After calling in the print- ers which are to receive a message, a sequence of characters such as "Carriage Return-Line Feed-Letters," is transmitted by the originating printer. This is known as the end of address code and causes the zero code bars of all printers to shift to the NON- SELECT position. The purpose of the "END OF ADDRESS" sequence of characters is to prevent un- called printers from receiving the message accidentally should their CDC be trans- mitted during normal message traffic. 4 End of Message-After the messages have been transmitted, it is desirable to place all of the printers in the select-non print condi- tion. This is accomplished by transmitting the conditioning code, "Figs-H-Ltrs." Being in the SELECT-NON-PRINT condition, the printers are standing by . . . their stunt boxes alert to line transmission. Approved For Release 2001/07/16 : CIA-RDP78S05452A000100040010-2 Approved For Release 2001/07/16 : CIA-RDP78SO5452A000100040010-2 conclusion OUTLOOK ... what of the future? W'd Teletype equipment, accepted as an important economic tool of business and industry, serves the nation in many ways. Military and civilian governmental agencies tie in their far flung outposts directly to control centers for fast dissemination, evalua- tion and disposition of information. With Teletype printed com- munications there is no misunderstanding. Major transportation users of Teletype equipment ... air lines, railroads, and over-the-road carriers ... maintain schedules, han- dle reservations, record manifests ... use Teletype units to com- municate in every way. Automobile manufacturers use the selective aspects of this equip- ment to produce "custom styling" for your automobile. Press associations use Teletype units to get news to all member papers simultaneously. The list is practically endless ... police, brokerage firms, hotels, chemical manufacturers, hospitals, Red Cross, steel companies, pipe lines, oil and gas refineries, universities, research organiza- tions, mines ... radio, electronic and computer systems manufac- turers . . . wholesalers, retailers, distributors in every field .. . telephone, telegraph and cable companies . . . these and many more, all use Teletype equipment. The stunt box plays an important role-for these users of Teletype products. The proven dependability and accuracy of precision made, lab and field-tested Teletype equipment, augmented by the versatile stunt box, assures maximum operating flexibility and efficiency. Every potential purchaser or lessee of communications, auto- mation or data processing equipment should investigate thor- oughly ... determine not only current, but consider future needs before making an equipment choice. Whatever the extent and complexity of the task ahead ... Teletype Model 28 equipment is better equipped to do the job. The acknowledged world leader in printed communications ... equipment that bears the trademark "Teletype" ... has more "BIG PLUS" features to offer. Operator at keyboard of Teletype Model 28 Send-Receive Page Printer. complete TELETYPE Model Jr'Iproduct t line of equipment is available 0 Model 2W ... to answer your specific questions Teletype TELETYPE CORPORATION GENERAL OFFICES application engineers will be pleased to help 5555 Touhy Avenue you to most efficiently apply Model 28 units to Skokie, Illinois Phone Ar C d 312 : ea o e your ved For ReIp c ~WT~d 7 5 2A000100040010-2 TWX: 910 910-223.-223-3811 (24-hour automatic answering service) W.U. service on premises TEIIf A: 09451 LITERATURE FREE Descriptive litera- ture concerning this equipment is youral~ i fortheasking.Plealse? indicate the u ,thati most intaeresL GOVERNMENT LIAISON OFFICE 425 13th Street, N.W. Washington 4, D.C_ Phone: MEtropolitan 8-1016 m. TELETYPE THE LEADERSHIP LINE