US3555186A - Key-operated teleprinter - Google Patents

Key-operated teleprinter Download PDF

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Publication number
US3555186A
US3555186A US724150A US3555186DA US3555186A US 3555186 A US3555186 A US 3555186A US 724150 A US724150 A US 724150A US 3555186D A US3555186D A US 3555186DA US 3555186 A US3555186 A US 3555186A
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Prior art keywords
transmission
bit
bit combination
store
character
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US724150A
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English (en)
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Adrian Allemann
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Hasler AG
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Hasler AG
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/38—Synchronous or start-stop systems, e.g. for Baudot code
    • H04L25/40—Transmitting circuits; Receiving circuits

Definitions

  • the invention relates to a key-operated teleprinter for the transmission of code symbols by the startstop method. These teleprinters operate in accordance with a code having five current steps, and in which each code symbol may have two meanings depending on whether it was preceded by a letter" code symbol or by a numerals code symbol.
  • the characters are divided into the group of letters and the group of numerals which also include the punctuation marks.
  • shifting between the two groups is effected by depressing a correspondingly marked key; accordingly the keys may be designated simultaneously with a character of the letter group and the corresponding character of the numeral group.
  • Keyboards are also known with separate keys for each character of the two groups and are therefore referred to as full keyboards.
  • Teleprinter transmitters are also known with full keyboards which automatically effect shifting between the two groups by automatically transmitting the corresponding shift symbol if a key of one group is depressed after a key of another group has previously been depressed, but this procedure necessitates complicated mechanical means which require constant maintenance.
  • this aim is achieved in a keyoperated teleprinter for the transmission of code symbols by the start-stop method and having a full keyboard, with an electronic transmitter store for storing the bits which: form the code symbol and an output circuit for the successive transmission of the stored bits to a transmission line by a system wherein in addition to triggering the bit combination, which represents the character, each key triggers a further bit which has a first value for all letters and a second value for all numerals, the said bit combination and the said further bit being, supplied to a reserve store which is adapted to store at least one bit combination and the associated further bit,.
  • a master clock which controls the transmission of the bit combination and of the associated further bit from the reserve store into the transmitter store and controls'the output circuit for transmitting the bit combination from said transmitter store to the transmission line, and means adapted to temporarily block the transmission of a bit combination to the transmission line if the aforementioned further bit, transmitted together with the bit combination, has a value which is different from that of the further bit transmitted with the preceding bit combination and, depending on said different value, produces an operating character for shifting the receiver from letters to numerals or numerals to letters respectively, transmits said operating character to the transmission line and then releases the temporarily blocked transmission of the bit combination.
  • An additional advantage achieved thereby is that the average keying speed is equal to the maximum transmission speed even in the event of irregular keying, individual characters being enabled to succeed each other at shorter intervals than those corresponding to the transmission time of one character,
  • FIGS. 1alg shows a summary of the circuit symbols employed to the extent to which they are not conventional;
  • FIG. 2 is a block circuit diagram of a key operated teleprinter unit comprising a plurality of circuit elements being summarized by symbols illustrated in FIG. 1 and explained hereinbelow.
  • FIG. 1a shows an AND-gate
  • FIG. 1b an OR-gate
  • FIG. 1c an inverter.
  • Inverters and gates can-be combined in which case the input or output of the gate is marked with a dot; for example, FIG. 1d shows an AND-gate with a blocking input designated by a dot at the input.
  • FIG. l f shows a shift register unit. The method of operation zofthis unit is explained by the adjacent circuit diagram.
  • Said circuit diagram contains two flip-flops FM and FFZ each having two input gates and one inverter.
  • the two positions which can be adopted by a flip-flop are designated with; 1 and 0; A flip-flop will be in position I if the output at the-designated side assumes the potential I. The output of the undesignated side will then be at the potential 0.
  • Application of a 1 potential to the input of the designated side sets the flip-flop to I while application of a 1 potential on the undesignated side sets it to O.
  • the unit is generally employed as a shift register when the inverted signal of a (a a',) is applied to the input a If the input I of the shift register unit changes to l, the input gates of the circuit will be rendered conductive and FFI is set to the position corresponding to the input (1,.
  • the second pair of gates is rendered conductive at the end of the t pulse and the position of FFl and FF2 is transmitted;
  • Both flip-flops can be set to 1 or 0 by means of the inputs s and r without reference to the inputs t and a a
  • the unit may however also operate at a counter for the pulses t: if both inputs a and a are set to I, F F1 will alter its position if 1 changes ml and will transmit this position to FF2 if 1 changes to O.
  • FIG. 1g refers to a simple flip-flop with two input gates and an inverter. If the clock input t changes to l, the flip-flop will assume position 0 or 1 correspondingto the potential. applied to the input a. Y
  • the teleprinter according to FIG. 2 comprises the following units separated from each other .in the drawing by dot-dash lines: a master clock I, a keyboard mechanism II with seven contacts TOto T6, only one of the contacts T1 to T5 being illustrated in the interests of simplicity and being referenced with Tl5, an electronic reserve store III, an electronic transmitter store comprising a part Na and a part IVb, a repeat system V, a shift system VI for shifting from letters to FIGS. and vice versa, an output circuit VII and blocking means VIII.
  • the master I clock contains a single pulse transmitter IG which operates continuously and supplies a square-wave voltage b having an identical pulse and interval period and a frequency of 400 c.p.s. This frequency is divided into two by the shift register unit A. The output frequency is once again divided into two by the shift register B is no signal t is present. In this case the output of B will appear via the OR-gate 0G on the input of a divider-by-8, comprising the shift registers D, E, F, but will be in operation only if M 1. When the divider is inoperative, D, E and F will be set to O.
  • the outputs of the divider-by-8-control a decoder D1 having eight outputs t t of which the-l potential is assumed by t when the counter is inoperative and successively by t to 1 when the counter is operative. If t 0, B will be set to zero and the bypass via the AND-NOT-gate U]. will be rendered conductive so that the output frequency of A will appear at the input of the divider.
  • the symbols T0-T6 refer to the contacts of a keyboard mechanism. This mechanism has a full keyboard, that is to say a separate key is allocated to each letter, each numeral and each symbol.
  • the contact T0 is closed whenever a key is depressed, and further a combination of the contacts TIT5 corresponding to the keyed character in the international tele graph code No. 2 and the contact T6 if the character is part of the numeral series of the aforementioned telegraph code. Coding is mechanical, and mechanical means prevent more than one key being simultaneously depressed.
  • Closing the contact TO sets an input pulse generator EG which delivers a delayed pulse whose minimum length is equal to at least 1 and whose maximum length is equal to at least 1 /2 cycles of the pulse generator IG, and which begins with b, that is to say at the end of a b pulse.
  • the beginning of the next b pulse causes the shift register All to be set and the pulse will appear at the output of A at the end of the b pulse.
  • the E0 pulse will appear at the inputs of contacts Tl-T6and is transferred to the inputs of the associated shift registers Al-A6 to the extent to which the contacts are closed.
  • the code symbol is recorded in the aforementioned shift registers when the aforementioned second I) pulse occurs, is transferred to the shift registers B1B6 when the third b pulse occurs and is transferred to the shift registers C1-C6 when the fourth b pulse occurs.
  • the 12 pulses reach the control inputs of the'shift registers via the AND-gates UA, UB, UC which are normally open.
  • the numeral bit, corresponding to the position of the contact T6, is transferred through the shift register A0, B0, C0 in the same way as the letter bits so that the position of the numeral bits always corresponds to that of the letter bits.
  • a third character can be stored in the A steps of the shift registers in the same way whereupon the output of OA changes to zero thus blocking the AND-gate UA. Accordingly, a mag net MS mounted in the keyboard mechanism above the inverter i8, is thus operated to prevent any further key being depressed.
  • the output t of the decoder D1 in the inoperative condition the output t of the decoder D1 will be set to 1, accordingly this will also apply to the input t of the OR-gate 0L, whose output is connected to the line L. Accordingly and in the inoperative condition the line will be continuously in condition 1, that is to say in a condition of continuous stop polarity.
  • the output of @L changes to O, that is to say to starL
  • Two successive and nonoverlapping pulses 1,, and 1 are formed during the period it, by a combination of the signals b, A, B, A, B.
  • the pulse in will trigger a signal 2 at the output of the gate UZ, said signal effecting the transmission of the position of the shift registers C0--C6 to the flip-flops 80-56,
  • the Z-pulse passes via the AND-gate U86 for transmission from C6 to S6, said AND-gate being blocked by the output of the decoder D2 as described subsequently, but being rendered conductive for the transmission of letters and numerals.
  • the signal Z also produces pulses at the outputs of the OR- gates 0C and OH to shift the data in the reserve register by one step (from A to B, from B to C).
  • the five AND-gates USl-US5 are successively rendered conductive by the pulses 1 the positions of the five shift registers Sl-SS being thus scanned and being transmitted to the line via the OR-gate 01.. in the aforementioned case the outputs of the gates UL2- -UL6 will be set to 0.
  • the input designated I, of the gate OL is set to l to transmit the stop polarity to the line.
  • a 1 will appear at the output of the gates UL2, UL3, ULS, UL6 during the periods t t If S 1, that is to say if Zi is to be recorded, a l'will appear during the period t, at the output of the AND-gate UL4, so that the character Bu (11111) is transmitted; the output of UL4 0 during the period t, for the character Zi so that the character Zi (l 101 l) is transmitted.
  • the output signal of H blocks the zero position of S0 during the period so' that the output of OM remains at l and the counter continues to operate for a'further'cycle.
  • the flip-flop K is however reset since its preceding position differed from S6 and it is now set tothe position of S6.
  • H will be set to zero, since K and S6 assume the same positions.
  • the signal contained in the store 81-85 will betransmitted to the line.
  • the telegraph code No. 2 incorporates a few characters whose significance is unaffected by any preceding shift to letters or numerals. These are the operating symbols:
  • Reversal of S6 should not be prevented if one of the keys Bu or Zi is to be depressed, but automatic transmission of a further Bu or Zi symbol is to be prevented.
  • Letter and numeral keys would not normally be required for the automatic transmission of characters, but they may be appropriate for certain functions, for example for signalling by repeated depressing of one or both keys.
  • the same character can be repeatedly transmitted in a simple manner by simultaneous depressing of the letter or numeral key and of the repeat key T7.
  • Depressing T7 sets the flip-flop W to l, but only at the time 1
  • the keyed letter is therefore first transmitted as described above.
  • the flip-flop W changes to l.
  • the AND- gate U2 is therefore blocked and the transmission of the 2 pulse and therefore the transmission of the next character from the store C to the store Sl-S6 is blocked.
  • the signal M appears continuously via the OR-gate OM at the input of the divider-by-S DEF which circulates continuously and effects the continuous transmission of the characters stored in the store Sl-S6.
  • the stores may be differently embodied, for example as magnetic stores, or they may be differently organized, the output store may function as shift register, the reserve store may operate in known manner as store with fixed data and floating input and output instead of operating as shift register with fixed input and output and floating data.
  • a keyboard-operated teleprinter for the transmission of code symbols by the start-stop method, with a full keyboard, with an electronic transmitter store for storing the bits which fonn the code symbols and an output circuit for the successive transmission of the stored bits to a transmission line, wherein in addition to triggering the bit combination which represents,
  • each key triggers a further bit which has a first value for all letters and a second value for all numerals, the said bit combination and the said further bit being supplied to a reserve store which is adapted to store at least one bit combination and the associated further bit, and a master clock which controls the transmission of the bit combination and of the associated further bit from the reserve store into the transmitter store and controls the output circuit for transmitting the bit combination from said transmitter store to the transmission line, and means adapted to temporarily block the transmission of a bit combination to the transmission line if the aforementioned further bit, transmitted together with the bit combination, has a value which is difierent'from that of the further bit transmitted with the preceding bit combination and, depending on said different value, produces an operating character for shifting the receiver from letters to numerals or numerals to letters respectively, transmits said operating character to the transmission line and then releases the temporarily blocked transmission of the bit combination.
  • a teleprinter having blocking means which blocks the aforementioned system when the bit combination corresponds to an operating character.
  • a teleprinter is a register in which the first bit combination transmitted into the empty register and the further bit associated therewith is store in a register step disposed nearest to the output of the register.
  • a teleprinter including a repeating system for the automatic and continuously repeated transmission of any desired character, triggered by depressing a repeat button wherein operation of the repeat button sets a flip-flop in a condition in which it blocks transmission of a bit combination and of the associated further bit from the reserve store into the transmitter store but not prior to the end of the transmission of a bit combination to the transmission line, furthermore causes the continuously repeated transmission of the bit combination stored in the transmitter store and IS reset into its inoperative position after releasing the repeat button but not before the end of transmission of a bit combination to the transmission line, whereupon the continuously repeated transmission is terminated.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Input From Keyboards Or The Like (AREA)
  • Document Processing Apparatus (AREA)
US724150A 1967-04-26 1968-04-25 Key-operated teleprinter Expired - Lifetime US3555186A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH591767A CH474925A (de) 1967-04-26 1967-04-26 Tastengesteuerter Fernschreibsender

Publications (1)

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US3555186A true US3555186A (en) 1971-01-12

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US724150A Expired - Lifetime US3555186A (en) 1967-04-26 1968-04-25 Key-operated teleprinter

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US (1) US3555186A (es)
BE (1) BE714301A (es)
CH (1) CH474925A (es)
DE (1) DE1294991B (es)
ES (1) ES353111A1 (es)
FR (1) FR1570063A (es)
GB (1) GB1192271A (es)
SE (1) SE332441B (es)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3725906A (en) * 1970-09-24 1973-04-03 Singer Co Self-timing code keyer
US3968324A (en) * 1974-03-18 1976-07-06 Siemens Aktiengesellschaft Circuit arrangement for synchronizing the letters/figures levels of several input and output devices in teleprinters

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3162725A (en) * 1962-01-23 1964-12-22 William M Oleson Character generator
US3296369A (en) * 1962-04-03 1967-01-03 Scm Corp Communications equipment keyboard

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3162725A (en) * 1962-01-23 1964-12-22 William M Oleson Character generator
US3296369A (en) * 1962-04-03 1967-01-03 Scm Corp Communications equipment keyboard

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3725906A (en) * 1970-09-24 1973-04-03 Singer Co Self-timing code keyer
US3968324A (en) * 1974-03-18 1976-07-06 Siemens Aktiengesellschaft Circuit arrangement for synchronizing the letters/figures levels of several input and output devices in teleprinters

Also Published As

Publication number Publication date
SE332441B (es) 1971-02-08
CH474925A (de) 1969-06-30
GB1192271A (en) 1970-05-20
DE1294991B (de) 1969-05-14
FR1570063A (es) 1969-06-06
BE714301A (es) 1968-09-16
ES353111A1 (es) 1970-01-16

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