US2183147A - Printing telegraph system - Google Patents

Printing telegraph system Download PDF

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Publication number
US2183147A
US2183147A US78348A US7834836A US2183147A US 2183147 A US2183147 A US 2183147A US 78348 A US78348 A US 78348A US 7834836 A US7834836 A US 7834836A US 2183147 A US2183147 A US 2183147A
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United States
Prior art keywords
code
marking
impulses
character
bar
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US78348A
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English (en)
Inventor
B Moore John
Richard E Mathes
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RCA Corp
Original Assignee
RCA Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to FR834156D priority Critical patent/FR834156A/fr
Application filed by RCA Corp filed Critical RCA Corp
Priority to US78348A priority patent/US2183147A/en
Priority to GB11570/37A priority patent/GB480150A/en
Priority to DER99294D priority patent/DE704242C/de
Application granted granted Critical
Publication of US2183147A publication Critical patent/US2183147A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
    • H03M13/47—Error detection, forward error correction or error protection, not provided for in groups H03M13/01 - H03M13/37
    • H03M13/51—Constant weight codes; n-out-of-m codes; Berger codes

Definitions

  • This invention relates to printing telegraph systems and more particularly to a system in which the circuits are subject to static interference and fading conditions.
  • Printing telegraph apparatus of the more generally used types employ five time elements for coding the signals representing each character to be printed. If these signals are sent over a radio channel or a carrier wave conductor channel they are very much subject to distortion and fading or to mutilation due to the presence 01' static impulses. The code signals, therefore, are liable to be received in an unintelligible form.
  • the master selector device at the receiver will lock out the printing mechanism and thereby prevent the printing of an incorrect character.
  • Figures 1 and 2 are code charts showing a specific arrangement of marking and spacing time elements suitable for selecting the type bars of a printing telegraph receiver to be actuated.
  • Dela- Fig. 3 shows in perspective certain details of a printer including the master selector bars and a few of the type bar selectors of which one is a selector for an error indicating type bar. Means are also shown for causing the printing mechanism to be locked out and the error indicating type bar to be selected when more or less than the proper number of marking impulses is received; and
  • Fig. 4 shows a circuit diagram ,of a modification of our invention wherein relays are used in place of step-by-step mechanical apparatus for obtaining the selection of the error indicating type bar when needed.
  • the Baudot code which is in general use in printing telegraph systems is composed of five permutational time elements in any one of which a-marking or spacing impulse may be transmitted.
  • the character significance of each code signal is determined by the order of sequence of the marking and spacing impulses.
  • a spacing impulse of fixed duration is utilized to start the printer in operation for selecting each transmitted character to be printed. This spacing impulse is immediately followed by the five-unit code signal and then comes a stop-impulse of indefinite duration to arrest the printer operation until another type key on the keyboard is depressed.
  • marking and spacing impulses required for character selection are the only ones to be herein considered since the use of additional impulses for operation of a printer by the start-stop method is op-' tional and our invention may be applied to a start-stop system as well as to a synchronous system.
  • marking and spacing impulses there are thirty-two possible combinations of marking and spacing impulses in the fiveunit code arrangement. That code makes maximum use of the circuit time and of the frequency band of a radio communications channel. It is, however, only suitable for use on a circuit which is free from interference. Fading or noise of any kind results in errors in the received copy. Its use on radio circuits is, therefore, relatively limited.
  • Another disadvantage of the five-unit code is that the number of combinations available is not suflicient to print all of the characters desired including letters, figures, punctuation marks, etc. Accordingly, it is the practice to employ a shift mechanism. It can easily happen that static impulses will produce such a code signal as to improperly actuate the shift mechanism at the receiving end when the transmitting machine is still unshifted. The intelligence thus becomes garbled even without the knowledge of the transmitting operator.
  • the arrangement of marking and spacing impulses as shown in Fig. 1 may be considered from the standpoint that it is suitable either for a seven-unit code or for a portion of an eightunit code.
  • the marking and spacing units may be according to the'showing in the first seven columns.
  • the marking and spacing units may be as designated in the eight columns of both Fig. 1 and Fig. 2. In this case it would usually be unnecessary to employ any code signals for shift and unshift as shown in Fig. 1.
  • every signal is composed of three marking impulses but these marking impulses are differently arranged with spacing impulses interspersed. It is equally possible that four marking impulses might be used with the remaining portion of each equal length code signal filled in by spacing impulses. It is also equally possible that a signalling code might be adopted in which each signal is composed of four marking and four spacing impulses arranged in different combinations.
  • FIG. 3 we show one embodiment of the receiving apparatus which is suitable for use with code systems having a fixed number of marking units in each character signal. Only those portions of a printing telegraph instrument are shown which relate to the invention.
  • the master selector includes the conventional code selector bars 5 over which are the type character selector bars 6. During the reception of a code signal any three of the bars 5 may be moved longitudinally to the left so as to bring into alignment certain notches 1 into which a selected cross bar 6 may drop. Only when the proper number of impulses is received during the time taken up by a seven-unit code signal will a type bar selector 6 be permitted to drop into these aligned notches. If more or fewer than three impulses are received, the cross bars 6 will, all of them, be held up by the raised portions of the selector bars 5.
  • This counting device includes an escapement wheel 8 mounted on a shaft 9 and permitted to rotate step-bystep when released by the escapement pawl mechanism H) which is pivoted on the rock-shaft II and is caused to oscillate by virtue of a cross bar l2 which engages with raised teeth l3 on the code selector bars 5.
  • a coiled spring H5 tends to unwind and to rotate the escapement wheel 8 in a counter clockwise direction with each release of one of its teeth from engagement with the escapement pawl Ill.
  • the escapement wheel is prevented from over-riding successive steps by the downward movement of the pawl member l5 into the gaps between the escapement wheel teeth.
  • Fig. 3 The various parts illustrated in Fig. 3 have been shown in the position which they would occupy after three of the code bars 5 have been actuated for selecting a character to be typed.
  • the escapement wheel 8 has, therefore, rotated three steps from its initial position. It must be understood, however, that these three steps will be taken regardless of which particular code bars 5 are actuated, although in the illustration it is shown that the' first three of these code bars viewed from the front of the device have been actuated.
  • a cam ll has been rotated through a like are so that a notch [8 in the face of this cam has come into alignment with a rider member I9 mounted on the end of the error indicating selector bar 20.
  • This bar 20 has accordingly been pulled slightly to the left under the traction of the spring 2
  • the selector bar 22 corresponding with the error indicating type bar has been restrained from dropping into the guide notches 23 of the code selector bars 5 by virtue of a raised portion 24 adjacent the notch N on the error selecting bar 20.
  • the notches 23 are purposely made wider than some of the other notches in these bars in order that the selection of the cross bar 22 may be effected solely in response to the actuation of the error bar 20.
  • One of the type bar selectors 6a has been shown in the figure as having been lowered into the notches of the code bars 5 where these notches were brought into alignment by the actuation of the first three of these bars and by not actuating the remaining four bars. If one of these four remaining bars had been actuated the escapement wheel would have taken a fourth step. None of the type bars for the printing of intelligence could be actuated in this case but in order to distinguish between the ommission of a character due to a faulty signal and a normal space between words, the error indicating type bar is preferably actuated by the mechanism shown. This actuation can take place either in response to a deficiency or an excess in the number of marking impulses in the code.
  • a rack and pinion mechanism connected in any suitable manner with the driving mechanism for the printer.
  • the rack bar 25 has been shown in the drawings as in its normal position, ready to make a restoring movement. This movement is longitudinal of the bar and during its stroke to the left it engages with the pinion 22 rotating the same clockwise so as to wind up the spring I4.
  • the pinion 22 is loosely mounted upon the shaft 9 in order that its rotative movements may always be through the same are regardless of the number of steps by which the escapement wheel 8 has been released.
  • a counting mechanism which comprises a system of relays as a substitute for the escapement wheel and escapement pawl mechanism shown in Fig. 3.
  • a counting mechanism which comprises a system of relays as a substitute for the escapement wheel and escapement pawl mechanism shown in Fig. 3.
  • Fig. 4 in which such an electrical relay system has been shown diagrammatically.
  • Figs. 3 and 4 corresponding parts, or parts possessing substantially the same functions, have been given like reference characters.
  • the code selector bars 5 have been similarly shown with teeth l3 and with notches 1 for selecting the type selecting cross bars 5.
  • the teeth I3 are caused to lift a lever 35 against the-pressure of a spring 31. This action takes place with each successive. movement of the code bars 5.
  • Contact is therebymade between the contact springs 38 so as to momentarilyclose' contact 4
  • the pin 32 tacts 45, relay 44, contacts 43, relay 49, and
  • both terminals of the relay 44 are at .the same potential.
  • relay 44 When relay 44 is energized the contacts 43 cause relay 48 to be locked up. Also the armature 42 of relay 44 is pulled away from the back contact 4
  • the second impulse may, there- 38, armature 42, contact 45, armature 59, contact 49, relay 41 and thence to ground.
  • relay 41 Upon the completion of this impulse and the opening of contacts 38, relay 41 locks up 'due to the closing of its contacts 5i and the establishement o a locking circuit from battery 39 through conta ts 45 and relay 52.
  • a circuit is now prepared through the front contact 53 and thence to the armature 54 of relay 55.
  • the third impulse initiated at contacts 38 may then be further traced through back contact 59 of relay 55 and relay 5'! to ground.
  • relay 55 When relay 55 is actuated in response to the opening of the contacts 38 and the closing of the locking contacts 58 a circuit is established from battery 39 through circuit breaking contacts 45 and the serially connected relays 55 and 51.
  • Relay 55 has two armatures 54 and 53 both of which are pulled up simultaneously upon the breaking of the impulsing circuit at the contacts '38. Armature 54 upon contacting with the front circuit breaking contacts 45, contacts 6.4 and 58' and thence through a magnet 52 to ground. The function of magnet 52 is to pull up its armature lever 55 to which is connected the error bar 29; In the embodiment of our invention shown in Fig. 4, the error bar 28 is normally held in position for selecting the type bar 22 having an error indicating character thereon. It is .only when a character selection consists of three markingimpulses, no more and no less, that the magnet 52 is actuated. The notch 25 is at that time withdrawn from beneath the bar 22 and prevents its selection. Any one of the type bars 5 may, however, be selected according to the code combination set up in the code bars 5.
  • the restoring bar 25 is mechanically actuated.
  • the mechanism for doing this has not been shown because it is well within the scope of an ordinary mechanic to provide it.
  • the relay system is thus prepared for counting the impulses of a succeeding code signal.
  • a plurality of type bar selectors means including a plurality of decoding elements cooperative with said selectors for making character selections only when a predetermined invariable number of said elements has been caused to respond to the controlling impulses of a code signal, an errorindicating device, and means controlled solely by the integration of said controlling impulses and operative in response to the reception of an excess or deficiency thereof within the time interval allotted to said code signal for actuating said error-indicating device.
  • a printing telegraph apparatus having a plurality of de-coding members each actuable in response to the reception of a marking element of a code signal, and type selecting elements each selectable only upon the actuation of a fixed normal number of said de-coding members other than one-half the total number thereof.
  • receiving apparatus having a plurality of decoding members each actuable in response to the reception of a marking element of a code signal, type selecting elements each selectable only upon the actuation of a fixed normal number of said decoding members, means including an additional type selecting element for indicating the reception of a mutilated signal and means rendered effective upon receipt of an abnormal number of marking impulses within a fixed time interval allotted to a code signal for then actuating said additional type-selecting element to cause an error-designating character to be printed in place of such character as would correspond to the signal before mutilation thereof.
  • code signal receiving apparatus a receiving printer having character selecting elements, de-coding means operable in response to signals having a permutational arrangement of marking and spacing units, the number of said marking units being in fixed ratio to the spacing units, for determining the sequence of operation of the character selecting elements, and. means operable in sole dependence upon a departure from said fixed ratio for causing said printer to print an error-designating character.
  • printing mechanism operable in response to the receipt of code signals having a uniform number of marking elements and a uniform number of spacing elements, an error-designating key, and means for actuating said key solely in response to the receipt of a signal which lacks conformity with the usual number of marking and spacing elements.
  • recording means responsive to code signals having a uniform number of elements of a certain characteristic plus elements of a different characteristic, an error indicating device, and means responsive to the receipt of a code signal having an abnormal number of elements of said certain characteristic for actuating said error indicating device, said means comprising a first series of impulse-responsive devices and a recond series of devices each responsive upon the cessation of an impulse through an associated one of said impulse-responsive devices, and circuits interconnecting the devices of the two series in such manner that they act as impulse counting relays for preventing the operation of said error indicating device upon reception of a correct code signal.
  • means responsive to character representing signals of equal length means to decode such of said signals as possess a normally fixed ratio between the number of marking and spacing units thereof, actuating mechanism responsive to the operation of said decoding means to print a designated code signal contains an excess or deficiency of marking elements with respect to said normally fixed number for preventing the selection of said type selecting elements.
  • a printing telegraph apparatus having a plurality of de-coding members each actuable in response to the reception of a marking element of a code signal, type selecting elements each selectable by an appropriate combination or a normally fixed number of said de-coding members, an error indicating device, and means effective whenever a received code signal contains an excess or deficiency of marking elements with respect to said normally fixed number for actuating said error indicating device.
  • a plurality of type bar selectors means including a plurality of decoding elements cooperative with said selectors for making character selections in response to the reception of any one of a number of different code signals all of which are characterized by an invariable number of controlling units, and means controlled solely by the integration of said controlling units and operative'in response to the reception of an excess or deflciency thereof within the time interval allotted to a single code signal for preventing the operation of the first said means.
  • a telegraph receiving system comprising means responsive to character representing signals of equal length, means to decode such of said signals aspossess a normally fixed ratio between the number of marking and spacing units thereof, apparatus under control of said decoding means for recording the characters represented by said signals. and a utilization device operable in response to the reception of a signal wherein the marking-to-spacing unit ratio is other than the one normally fixed.

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  • Physics & Mathematics (AREA)
  • Probability & Statistics with Applications (AREA)
  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Cash Registers Or Receiving Machines (AREA)
  • Printers Characterized By Their Purpose (AREA)
  • Electronic Switches (AREA)
US78348A 1936-05-07 1936-05-07 Printing telegraph system Expired - Lifetime US2183147A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
FR834156D FR834156A (enrdf_load_stackoverflow) 1936-05-07
US78348A US2183147A (en) 1936-05-07 1936-05-07 Printing telegraph system
GB11570/37A GB480150A (en) 1936-05-07 1937-04-22 Improvements in or relating to printing telegraph systems
DER99294D DE704242C (de) 1936-05-07 1937-05-08 Drucktelegrafensystem

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US78348A US2183147A (en) 1936-05-07 1936-05-07 Printing telegraph system

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US2183147A true US2183147A (en) 1939-12-12

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US78348A Expired - Lifetime US2183147A (en) 1936-05-07 1936-05-07 Printing telegraph system

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US (1) US2183147A (enrdf_load_stackoverflow)
DE (1) DE704242C (enrdf_load_stackoverflow)
FR (1) FR834156A (enrdf_load_stackoverflow)
GB (1) GB480150A (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2508554A (en) * 1948-03-06 1950-05-23 Rca Corp Error detector for start-stop telegraph printers
US2512038A (en) * 1947-06-07 1950-06-20 Martha W C Potts Error detecting code system
US2552126A (en) * 1946-10-24 1951-05-08 Hendrik C A Van Duuren System for the transmission of telegraph signs on a radio path by means of a double wave
US2614210A (en) * 1944-05-18 1952-10-14 Rca Corp Pulsed radio signaling
US2622148A (en) * 1948-03-15 1952-12-16 Nederlanden Staat Error detector for telegraph printer codes
US2696599A (en) * 1953-02-12 1954-12-07 Bell Telephone Labor Inc Check circuits
US2759998A (en) * 1951-10-26 1956-08-21 Itt Pulse communication system
US2770304A (en) * 1951-12-21 1956-11-13 Ibm Relay storage unit
US2860325A (en) * 1952-03-31 1958-11-11 Sperry Rand Corp Information translating apparatus
US2883255A (en) * 1954-04-28 1959-04-21 Panellit Inc Automatic process logging system
DE1218472B (de) * 1955-09-20 1966-06-08 Commercial Controls Corp Elektrische Steuereinrichtung fuer eine Maschinenkombination, bestehend aus einer tastenbetaetigbaren elektrischen Schreibmaschine, einer Lochvorrichtung und einer Abtastvorrichtung

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE871770C (de) * 1937-09-25 1953-03-26 Staatsbedrijf Der Posterijen Typendrucktelegraphensystem
DE880314C (de) * 1939-05-04 1953-05-07 Staatsbedrijf Der Posterijen Drucktelegrafensystem mit Gegenverkehr, insbesondere fuer drahtlose UEbertragung

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2614210A (en) * 1944-05-18 1952-10-14 Rca Corp Pulsed radio signaling
US2552126A (en) * 1946-10-24 1951-05-08 Hendrik C A Van Duuren System for the transmission of telegraph signs on a radio path by means of a double wave
US2512038A (en) * 1947-06-07 1950-06-20 Martha W C Potts Error detecting code system
US2508554A (en) * 1948-03-06 1950-05-23 Rca Corp Error detector for start-stop telegraph printers
US2622148A (en) * 1948-03-15 1952-12-16 Nederlanden Staat Error detector for telegraph printer codes
US2759998A (en) * 1951-10-26 1956-08-21 Itt Pulse communication system
US2770304A (en) * 1951-12-21 1956-11-13 Ibm Relay storage unit
US2860325A (en) * 1952-03-31 1958-11-11 Sperry Rand Corp Information translating apparatus
US2696599A (en) * 1953-02-12 1954-12-07 Bell Telephone Labor Inc Check circuits
US2883255A (en) * 1954-04-28 1959-04-21 Panellit Inc Automatic process logging system
DE1218472B (de) * 1955-09-20 1966-06-08 Commercial Controls Corp Elektrische Steuereinrichtung fuer eine Maschinenkombination, bestehend aus einer tastenbetaetigbaren elektrischen Schreibmaschine, einer Lochvorrichtung und einer Abtastvorrichtung

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Publication number Publication date
FR834156A (enrdf_load_stackoverflow) 1938-11-15
GB480150A (en) 1938-02-17
DE704242C (de) 1941-03-26

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