US2421169A - Automatic telephone system directed with the aid of revertive audio-frequency signals - Google Patents

Automatic telephone system directed with the aid of revertive audio-frequency signals Download PDF

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Publication number
US2421169A
US2421169A US537564A US53756444A US2421169A US 2421169 A US2421169 A US 2421169A US 537564 A US537564 A US 537564A US 53756444 A US53756444 A US 53756444A US 2421169 A US2421169 A US 2421169A
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Prior art keywords
line
calling
station
switch
circuit
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Expired - Lifetime
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US537564A
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English (en)
Inventor
Taylor Reginald
Baker George Thomas
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Automatic Electric Laboratories Inc
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Automatic Electric Laboratories Inc
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/58—Arrangements providing connection between main exchange and sub-exchange or satellite
    • H04Q3/62—Arrangements providing connection between main exchange and sub-exchange or satellite for connecting to private branch exchanges
    • H04Q3/625—Arrangements in the private branch exchange
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B5/00—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture
    • C03B5/12—Melting in furnaces; Furnaces so far as specially adapted for glass manufacture in shaft furnaces

Definitions

  • the present invention relates to electrical signalling systems, and offers considerable advantages in its application to automatic telephone systems.
  • Theflinven'tion is moreover particularly suitable for use in small private automatic telewith an automatic switch to cause it during its operation to transmit back to the calling party an audible signal for indicating the identity of the line with which it is associ'ated at any time.
  • signalling .arrangements are provided for notifying a calling party of the progress of the movement of an automatic switch and for effecting its arrest when it has reached the appropriate point.
  • a furtherfeatu re of the invention is that in an automatic telephone or like signalling system having connections set up over "automatic switches located at a central point, a calling party is enabled by suitable separate operations at the substation to prepare a switch for operation, to initiate its movement and to bring'it to rest when it has reached the appropriate point.
  • Another feature of the invention is that in an automatic telephone or like signalling system having connections set up over automatic switches located at a central 'point the setting of an automatic switch is adapted to be initiated by a signal from a calling substation and-thereupon continues until terminated by a inr-ther signal from the substation or the switch reaches the end of its traveL-the position of the switch being continuously indicated to the calling party.
  • a still further feature of the invention is that in an automatic telephone or like signalling system'having connections set up over automatic switches located at a central point each station having associated with it a switch having access to all the other stations, each switch is adapted to be operated by locally generated impulses as long as a calling party at the associated station maintains-his line in a characteristic condition 2 'or until the switch reaches the end of its travel, characteristic signals being transmittedbackto the calling-party to-notify him of the progress of the switch.
  • the P. A. X to be described employs sound-powered hand-microtelephonesea-ch'of whichinclu'des a handset: push button which-is permanently bridged by a condenser.
  • the -restof 'the'instrument merely consists :of a hook or rest on which the handset is accommodated-when not inuse.
  • the dials, bells and induction coils usuallyprovi'ded on P. A. X telephone instruments are dispensed with.
  • To-Set' up'a-call the push button on the handset is depressed and is then released.
  • For each step of theswitcn-a tone pulse is applied to the calling line so as to enable the subscriber to count the stepsof the switch and so be aware when ithas positioned itself on the :reauiredv line.
  • the push "button on the handset is again depressed and this results inthe arrest of the switch and-the setting upoi a calling'condition on the desired line.
  • the wanted artys attention is attracted by continuous tone current irom the exchange equip- .mentextendedover his-line to actuate the serieseonnected.sound-.-poweredtransmitter-and. receiver.
  • the terminationof the tone pulses indicates 3 to the calling subscriber that the called subscriber is being rung.
  • the tone pulses continue after the depression of the push button by the calling party.
  • the calling party will restore the button and the switch will proceed to step on to its home position when the line circuit will be ready for further calls.
  • the mains-driven synchronous motor SM drives the two interrupters II and I2, the former providing 165 m. s. earth pulses at spacings of the same order for the purpose of stepping the line circuit rotary switches and the latter providing on lead ITL 165 m. s. tone pulses which are synchronised with the stepping impulses applied to lead IPL. For ringing purposes continuous tone is used, and this is available from lead CTL.
  • relay C falls away and if at this time there is an earth on the pulse lead IPL, relay H will remain held and will only release to connect up this lead to the bank SS5 when the earth is removed from lead IPL, relay H thus providing a pulse guard feature.
  • the next earth pulse received over lead IPL moves the SS switch to position 2 from which position access can be had over wipers and banks SS2 and SS3 to the line of subscriber No. I.
  • a tone pulse is transmitted over lead ITL and bank and wiper SSI to the calling partys receiver, and since as previously mentioned these tone pulses are synchronized with the stepping pulses, the tone pulse will persist until termination of the stepping pulse which advanced the switch to position 2.
  • a tone pulse is returned to the calling party and, assuming that subscriber No. 8 is required, after eight tone pulses have been heard, 1. e. when the SS switch has been set to position 9 which connects with subscriber 8, the push button is again depressed and this re-operates relay C which opens the switch driving circuit.
  • a testing circuit is provided for relay H over wiper and bank SS4 to the wanted line and if this line is free, relay H will energise in series with the H relay of the wanted line, the circuit extending over wiper SS4 in position 9, and the multiple wiring to the bank SS4 in No. 8 line circuit. In this circuit the P lead No.
  • the calling relay H in operating switches the calling line through to the wipers and banks SS2 and SS3, disconnects the tone pulse circuit to the calling party and further disconnects the magnet driving circuit, while relay H of the called line No. 8 in operating extends continuous tone over lead CTL onto line No. 8.
  • the associated C relay When the called subscriber answers by depressing his push button, the associated C relay operates and steps the relevant SS switch to the second position, thus cutting off the calling signal at wipers and banks SS2 and SS3 and at the same time completing a conversational path.
  • the called partys relay H is held independently of the SS switch banks and wipers.
  • relay H In case the wanted line is busy, on the operation of the relay C in the calling line circuit after the requisite number of tone pulses have been heard, relay H is unable to operate since, owing to the fact that the SS switch in the called line is off-normal, the battery potential normally supplied to the relevant P lead is disconnected. With the calling line circuit relay H normal the tone pulses continue to be sent to the calling subscriber over bank and wiper SSI. The motion of the switch SS is, however, halted due to the operation of relay 0.
  • relay C releases, whereupon relay I-I releases in turn, after fulfilling its pulse guard function, and re-connects the pulse lead IPL to bank SS5 and the switch SS proceeds to rotate through to the home position.
  • step-on facility if for example subscriber No. 5 after gaining access to subscriber No. 8 wishes to speak to subscriber No. 9 or Hi, all that is necessary after terminating the conversation with subscriber No. 8 is for him to continue to hold his handset against his ear and also to release his push button, whereupon the SS switch will step on and will return a tone pulse for each step. After the one or two steps necessary to gain access to subscriber No. 9 or 10 have been taken, the push button is again depressed and the called subscriber is then rung in the usual manner.
  • a priority facility may be readily obtained by permanently strapping the H3 contacts on the line circuits of all subscribers entitled to this facility, in which case cut-in to the desired line will take place regardless of whether it is busy or not.
  • tone pulses As an alternative to the tone pulses, arrangements might be made for audible announcement to-calling parties'of the numbers of the lines as they are successively connected with, but this would involve appreciable additional expense and complication.
  • the difficulty may be readily overcome b providing locking facilities on the push button.
  • a more satisfactory alternative therefore is to makeuse of a cradle'switch of ordinary type for closing the line circuit, only the control of the movement of the switch being elfected from the push button which in this case is arranged to open normally closed contacts in the line circuit.
  • the likelihood of the-line equipment being tied up by a forgetful subscriber is then no greater than with a normal instrument.
  • a board according to the invention could, with some modification, be adapted to give tie line facilities to another board or boards of the same type.
  • P. A. X board has been provided in which the total of the local and exchange apparatus per lineis in effect ahandset, twov minor type relays and a small rotary selector switch, andin-which, due'to-the elimination of link circuits which form an economic point of view are gea -mes normally limited to one or twoau'n lines, all the subscribers on-the board can be on conversation pairs at the same time, that is to say, full availability-conditions are obtainable at all times.
  • the invention- is not limited in application to the-use of sound-powered telephones as ordinary telephone instruments might be used.
  • P. A. X use this would, however, increase :thecost both-of the board and ofthe subscribersinstruments, since standard ringing andring trip arrangements would be needed in the line circuits, induction coils and bells would 'berequiredin the telephone instruments.
  • the invention is moreover not limited to cases where only a single digit is required as the general principles could readily be applied to larger networks where two or even more digits are-involved in turn and control is effected by repeated operation of the push button. Furthermore the invention is not restricted to private exchange networks and may infact offer valuable. advantages in connection with rural networks where the standard of maintenance of the sub-- scribers lines is not sufiiciently high to permit satisfactory calling in the normal manner by trains of impulses but is good enough to permit tone signals'to be effective and enable control to becarried out by a single opening and closing of the line circuit.
  • a plurality of telephone substations each including a receiver, an exchange, lines connecting each'of the substations to 'the'exchange, switching means in the exchange having a plurality of selecting positions each corresponding to one of said substations, means controlled over acalling one of said lines for initiating the operation ofsaid switching means, means in theexchange for thereafter causing said switching means to be successively advanced through said plurality of selecting positions and for concurrently transmitting series of audio frequency impulses over the calling line, each of said impulses corresponding to one of said selecting positions, said impulses causing audible signals to be produced by the receiver at the calling substation to indicate the progress of said switching means, saidsecond means being controlled over the calling line to stop the advancement of said switching means when it hasreached a positioncorresponding to a desired station.
  • a testing circuit associated with said switching means, and means controlled over said testing circuit for causing the transmission of said audio frequency impulses to be continued in the event that said switching'means is stopped in a position corresponding to a station that is busy.
  • a control station a controlled station including switching means having a plurality of selecting positions, a line extending between said stations, means at said control station for completing a direct current circuit over said'line to cause said switchingmeans to perform an initial switching operation, said switching means being thereafter responsive to subsequent opening of said direct current circuit at the control station to advance itself through said pluralityof selecting positions and to transmit a series of alternating'current impulsesover said line, means at said control'station responsive to said impulses for indicating the progress of saidswitching means, the advancement of said switching means being stopped in response to the 7 reclosure of said direct current circuit at the control station when a desired selecting position has been reached.
  • a signaling system as claimed in claim 3 in which said switching means is arranged to return to its initial position in the event that said direct current circuit is not reclosed at the control station.
  • a signaling system as claimed in claim 3 in which said switching means is responsive to a second opening of said direct current circuit to advance itself through subsequent selecting positions.
  • a plurality of tele-- phone stations each including a receiver, a selector switch associated with each of said stations, each of said switches having a plurality of selecting positions each corresponding to one of said stations, means controlled by a calling one of said stations for initiating the operation of its associated selector switch, common mean thereafter causing said selector switch to be successively advanced through said plurality of selecting posi-- tions and transmitting a series of audio frequency impulses to the calling station, said impulses causing audible signals to be produced by the receiver at the calling station whereby a subscriber thereat can determine the progress of said selector switch, said first means being controlled by the calling station to stop the advancement of said selector switch when it has reached a selecting position corresponding to a desired station.
  • said first means comprises a relay which is operated and restored to initiate the operation of said selector switch, said relay being reoperated to stop the advancement of said selector switch by said common means,
  • a telephone system a plurality of telephone stations, a pair of relays and a selector switch for each of said stations, each of said switches having a normal, an answer, and a plurality of calling positions, a first relay of each of said pairs being operative under the control of its corresponding station to cause the corresponding selector switch to be advanced into any of said calling positions in order to associate two of said stations, the second relay of the pair corresponding to the calling one of said two stations operating to prepare a talking circuit between said two stations and the second relay of the pair corresponding to the called one of said two stations operating to signal the called station in response to said association, the first relay of the pair corresponding to the called station operating in response to an answer therefrom to cause the corresponding selector switch to be advanced to the answer position in order to stop the signaling of the called station and to complete the talking circuit between said two stations.
  • a telephone system as claimed in claim 9 including circuit arrangements preventing operation of the second relay of the pair corresponding to the calling station if the called station is in use, thereby causing a busy indication to be returned to the calling station and preventing interference with the called station.
  • a telephone system as claimed in claim. 9 including circuit arrangements normally preventing operation of the second relay of the pair corresponding to a calling station if the calling position to which the selector switch thereof is advanced is occupied by a selector switch corresponding to another station, and further circuit arrangements causing the second relays of the pairs corresponding to calling stations to operate when the selector switches thereof are advanced to particular calling positions despite the busy condition thereof, whereby conference service may be established between three or more of said stations.
  • a first station including a progressively movable device having a plurality of operating positions, a line extending between said stations, means at said first station for completing a direct current circuit over said line, means at said second station operated in response to a subsequent opening of the direct current circuit completed over said line from said first station for causing said device to be moved through said plurality of operating positions and for causing a series of impulses each comprising alternating current to be transmitted over said line, means at said first station responsive to said impulses for indicating the progress of the movement of said device, the movement thereof being stopped by the operation of said second means in response to the reclosure of the direct current circuit at said first station when a desired operating position has been reached.
  • a first station a second station including a progressively movable device having a plurality of operating ositions, a line extending between said stations, means at said first station for completing a direct current circuit over said line, means at said second station operated in response to a subsequent opening of the direct current circuit completed over said line from said first station for causing said device to be moved through said plurality of operating positions and for causing a series of audio frequency impulses to be transmitted over said line, means at said first station responsive to said im pulses for audibly indicating the progress of the movement of said device, the movement thereof being stopped by the operation of said second means in response to the reclosure of the direct current circuit at said first station when a desired operating position has been reached.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Astronomy & Astrophysics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Devices For Supply Of Signal Current (AREA)
  • Interface Circuits In Exchanges (AREA)
US537564A 1943-07-08 1944-05-27 Automatic telephone system directed with the aid of revertive audio-frequency signals Expired - Lifetime US2421169A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB11075/43A GB566779A (en) 1943-07-08 1943-07-08 Improvements in electrical signalling systems

Publications (1)

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US2421169A true US2421169A (en) 1947-05-27

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US537564A Expired - Lifetime US2421169A (en) 1943-07-08 1944-05-27 Automatic telephone system directed with the aid of revertive audio-frequency signals

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US (1) US2421169A (en))
ES (1) ES166712A1 (en))
FR (1) FR932188A (en))
GB (1) GB566779A (en))
NL (1) NL63260C (en))

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2530802A (en) * 1944-01-12 1950-11-21 Automatic Elect Lab Telephone system employing finder switches for connecting calling lines to numericalswitches
US2623164A (en) * 1948-11-01 1952-12-23 Automatic Elect Lab Single channel, single frequency, mobile radio telephone system
US2740841A (en) * 1953-01-16 1956-04-03 Itt Automatic rural crossbar switching system
US3234514A (en) * 1958-12-12 1966-02-08 Int Standard Electric Corp Electric pulse signalling system having switching means connected to a constant-voltage source
US3562434A (en) * 1967-03-31 1971-02-09 Nippon Electric Co Interoffice signaling system employing selected ones of the touch-tone telephone frequencies for establishing interoffice connections

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1137223A (en) * 1914-03-02 1915-04-27 Western Electric Co Machine telephone switching system.
US1367583A (en) * 1918-04-02 1921-02-08 Bornett L Bobroff System for signaling
US1600358A (en) * 1923-12-27 1926-09-21 Coventry Autom Telephones Ltd Remote-control system
US1778077A (en) * 1924-10-11 1930-10-14 American Telephone & Telegraph Remote-control system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1137223A (en) * 1914-03-02 1915-04-27 Western Electric Co Machine telephone switching system.
US1367583A (en) * 1918-04-02 1921-02-08 Bornett L Bobroff System for signaling
US1600358A (en) * 1923-12-27 1926-09-21 Coventry Autom Telephones Ltd Remote-control system
US1778077A (en) * 1924-10-11 1930-10-14 American Telephone & Telegraph Remote-control system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2530802A (en) * 1944-01-12 1950-11-21 Automatic Elect Lab Telephone system employing finder switches for connecting calling lines to numericalswitches
US2540644A (en) * 1944-01-12 1951-02-06 Automatic Elect Lab Allotter switch for preassigning idle finder switches
US2623164A (en) * 1948-11-01 1952-12-23 Automatic Elect Lab Single channel, single frequency, mobile radio telephone system
US2740841A (en) * 1953-01-16 1956-04-03 Itt Automatic rural crossbar switching system
US3234514A (en) * 1958-12-12 1966-02-08 Int Standard Electric Corp Electric pulse signalling system having switching means connected to a constant-voltage source
US3562434A (en) * 1967-03-31 1971-02-09 Nippon Electric Co Interoffice signaling system employing selected ones of the touch-tone telephone frequencies for establishing interoffice connections

Also Published As

Publication number Publication date
NL63260C (en))
ES166712A1 (es) 1944-08-16
GB566779A (en) 1945-01-12
FR932188A (fr) 1948-03-15

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