US2485580A - Signaling system - Google Patents

Signaling system Download PDF

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Publication number
US2485580A
US2485580A US697670A US69767046A US2485580A US 2485580 A US2485580 A US 2485580A US 697670 A US697670 A US 697670A US 69767046 A US69767046 A US 69767046A US 2485580 A US2485580 A US 2485580A
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US
United States
Prior art keywords
relay
circuit
call
frequency
signal
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
US697670A
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English (en)
Inventor
Robert C Ferrar
Menhennett Gerald
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.)
STC PLC
Federal Telephone and Radio Corp
Original Assignee
Standard Telephone and Cables PLC
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 GB630815D priority Critical patent/GB630815A/en
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to US697670A priority patent/US2485580A/en
Priority to CH276571D priority patent/CH276571A/de
Priority to ES0181845A priority patent/ES181845A1/es
Application granted granted Critical
Publication of US2485580A publication Critical patent/US2485580A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/02—Terminal devices
    • H04W88/022—Selective call receivers
    • H04W88/025—Selective call decoders
    • H04W88/027—Selective call decoders using frequency address codes

Definitions

  • This invention relates to systems for selectively calling stations in a communication system and for signalling the call.
  • An object of the invention is to call a particular desired station, place it in operating condition and to signal the operator thereof.
  • Another object is to provide a signalling system capable of signalling the operator when a call is coming in, and if not received by an operator, to leave an indication that a call has been attempted.
  • signalling means either audible or visual or both, to let the operator know that a call is being made, this being desirable since the receiver is provided with earphones instead of a loudspeaker.
  • These signals are produced by a ringing signal after a control circuit has conditioned the receiver in response to a calling signal.
  • the system includes a second control circuit which operates in coordination with the first or main control circuit. The two control circuits control the signalling devices so that one or both operate while the call is attempted and thus maintains at least one in signalling condition until the operator lifts the earphones.
  • the figure shows an arrangement according to our invention, adapted to be incorporated into a receiver of the frequency modulation type.
  • the tube l represents an audiofrequency power amplifier which may be any desired type of power amplifier; and as the particular type is unimportant, all of its electrodes are not shown, but only the output electrode or anode 2.
  • Power amplifier l is part of the receiver and it is coupled through an output transformer 3 to earphones 4.
  • this audio-amplifier Upon being called from the central station, this audio-amplifier is adapted to be made operative by the system shown connected with it.
  • the system operates on audio-frequency and its input is connected over a lead 5 from the output of the usual discriminator of a frequency modulation receiver, through a coupling condenser 6 to the control grid 7 of an audio-frequency amplifier tube 8 of the triode type.
  • the anode 9 has its output connected to a coil which is electromagnetically related with a number of tuned reeds of which there are shown three, these being numbered ll, l2 and I3.
  • the reeds are each tuned to a different natural frequency in the audio-frequency range so that when the tuned frequency is sent through coil [0, the corresponding reed will vibrate against the respective reed contacts l4, l and 16.
  • Reed I I has connected in series between it and ground a high resistance ll; reed I2 is connected to ground through a series arranged resistor 18 and condenser l9; and'reed I 3 is connected directly to ground.
  • Contacts l5 and I6 are connected together and are connected to ground through two parallel paths, one of which comprises the series-connected condenser 20 and resistor 2!, and the other of which comprises the series arranged resistor 22 and condenser 23.
  • a thyratron tube 24 For the purpose of controlling the audio power amplifier I, in accordance with called signals, there is provided a thyratron tube 24, the control grid 25 of which is connected to points 26 and 21 which are the points between condenser 20 and resistor 2
  • the output circuit of the thyratron connected to its anode 28 passes through a relay coil 29 having a pair of armatures 3i! and 3
  • Contact 32 has connected to it a voltage source 34 for supply of negative bias for tube 24.
  • the armature 3B is connected over lead 35 to the grid 25 of the thyratron, so that when the armature closes on its contact 32, the negative bias is connected to the thyratron grid to shut off the thyratron.
  • the armature contact 33 is connected over lead 36 to the lower end of a resistor 31 which is connected in series with relay coil 29.
  • is connected over a lead 38 to the lower side of the primary winding of output transformer 3, so that when armature 3
  • contact 3 3 may not be connected to the primary of transformer 3, the latter in that case being connected directly to the power source. With such a connection the receiver would. always be operative upon reception of the carrier to which it is tuned, the control circuit serving only as a control for the signalling: equipment.
  • reed II has a natural frequency of vibration at a frequency X somewhere in the low audio range
  • reeds l2 and I3 have somewhat diiferent natural frequencies Y and Z, also in the low audio frequency range.
  • the operator at the central station will have a number of calling keys, or dialv with a plurality of'keying positions, each of which will frequency modulate his transmitting carrier frequency by a sustained note somewhere preferably in thelow audio range.
  • the operator will first dial or push his key for the X audio frequency; and when the receiver picks up the signal frequency modulated by the X signal, the discriminator will separate out the X frequency in the usual way and send it to audio amplifier 8'. Since the reed operating coil ill will carry this note, it will vibrate the reed H without vibrating either of reeds I 2 or l3 since the latter two reeds are not naturally resonant at this frequency X.
  • the operator will dial or push the next call signal Y, which will cause reed I2 to vibrate against its contactor l5. at. the low audio rate, and this will cause a current. from the charged condenser l-il to pass through condenser 20, thereby charging up condenser 28, the charging circuit for condenser 20 being through the. parallel-arranged elements: 2i and 23 and the conductive grid-cathode circuit of the thyratron tube 24.
  • the charge on condenser 29' will gradually leak oif through the resistance. connected across it, but before this happens, the operator at the calling station will; dial or pushhis Z button to vibrate reed l3 against its contact I6, thereby connecting the positively polarized upper end of the condenser 20' to ground intermittently, and
  • the cessation of conduction in the thyratron causes the D.-C. current in the relay coil 29 to drop to zero, so that the armatures 30 and 3
  • the closureof these relay contacts performs two functions: The closure of armature 3
  • the central station discontinues the signal, the cessation of the carrier at the limiter grid causes thermal agitation noise output from the lilniter'stage of the receiver.
  • This noise voltage is applied through condenser 39 to'grid 2 5 thereby trigging thyratron tube 24, and allowing the thyratron to begin to conduct again.
  • the. invention may be used to call individuallyany one of a number-0f stations, the number being dependent only on the number of reeds per station, and. the number of audio-frequency call signals per system. If; N'be the number ofreeds per second, and Tthe number of call tones available at; the controlstation, the number ofremote stations: which may be individually called is:
  • the element-40 is connected in; circuit-with the associated contact M between the'grid 25:by.con-- nection 42 and a negative voltagescurceby connection 43;
  • the figure of the drawing shows audible and visual indicating means for indication of a call signal and if not answered to leave an indication that a call has been attempted.
  • the signalling portion of the circuit includes an audible signalling device 44 which may comprise a bell and the visual indicating device 45 which may comprise a light bulb. These .two devices are controlled by a relay comprising a coil 46 and three switches 41, 48 and 49.
  • the bell 44 is connected in circuit with switch 3
  • the light bulb 45 is connected between ground and by connection 5! through switch 48 and connection 52 to battery B.
  • the relay 46 is controlled by circuit 53 which includes a reed 54 and contact 55, connection 56, switch 3
  • the relay 46 is further controlled by the earphones 4.
  • the receiver hook 60 is provided with a switch 6
  • a control circuit adapted to be called from another station
  • a call indicating circuit means including vibratory station selector apparatus-operating responsive to a station selector signal to cause said control circuit to condition said call indicating circuit, and vibratory means responsive to a further received signal to energize said call indicating circuit.
  • said indicating means includes an audible indicator and a visual indicator, each operable upon reception of said further signal, and means to maintain one of said indicators operative after termination of an attempted call.
  • a receiver station adapted to be called from another station; a first control circuit, a second control circuit conditioned only by operation of said first circuit, first and second signalling devices, the first being conditioned by operation of said first control circuit but both being controlled by energizatlon of said second control circuit, means responsive to a carrier modulated with a predetermined signal for operation of said first control circuit, means responsive to a further modulation signal to energize said second control circuit, said .first control circuit being held in operative condition so long as said carrier is received, and means to maintain said second control circuit energized until an attempthas been made to receive the call.
  • signal responsive means adapted to be energized by a predetermined signal with which a carrier is modulated, a first relay normally maintaned in open position, means to move said first relay to closed position upon energization of said signal responsive means, a second relay normally maintained in open position, means responsive to reception of a further predetermined signal after prior closure of said first relay to actuate said second relay to closed position, a signalling device operable upon closure of both relays, means for reproducing intelligence signals received by said station, means controlled by said first relay for controlling reproduction by said reproducing means, and means associated with said reproducing means to maintain said second relay closed upon closure thereof until said reproducing means is used to receive a call.
  • an electromagnet adapted to be energized by signal frequencies with which a given carrier is modulated, a plurality of vibratory elements each resonant at its respective signal frequency, a first relay normally maintained in open position, means to move said first relay to closed position upon resonant operation of at least one of said vibratory elements, a second relay normally maintained in open position, means responsive to resonant operation of another of said vibratory elements only after prior closure of said first relay to actuate said second relay to closed position, a signalling device operable upon closure of said second relay, a signal reproducing means, means controlled by said first relay for controlling reproduction by said reproducing 7: means; and? means: associated with, said; repmduc'-- ing means to maintainqsaid; second; relay: closedupon closure thereof until said reproducing means is -used to receive acall.
  • said second relay-"to closed position a first signalling device; operable only upon, closure ofboth: relays, a second. signallingdevice operable upon closure: of said second relay, signal reproducing, means, means: controlled by said first relay'for controllingreproduction by said reproducing means, and means associated: With: said reproducing meansto: maintainsaid second relay closed upon closure thereof until said reproducing means: is used to receive'a call.
  • an electromagnet adapted tobe energized by signal frequencies with which a given carrier ismodulated, a plurality of vibra-- tory elements each resonant at its respective signal frequency, a first relay, an oscill'atory'circuit normally operative to maintain said first relay in-open position, means responsive to resonant' operation of at least oneof said vibratory elements to stop oscillations'insaid circuit, thereby enabling said first relay to close, a second relay normally maintained in open position, meansresponsive to resonant operation of another of said vibratory elements only after prior closure of said first relay to actuate said second relay-toclosed position, a, first signalling; device: operableonly upon closure ofbothrelays, and a second signalling device operable uponclosuro ot saidsecondrelay.
  • a receivingstation adapted to:- be called.: from: another station, anelectromagnet. adapted: tobeenerglzed bysignal frequencies withw which. a given carrier is modulated, a pluralityof vibra tory elements eachresonant: at its respective; signal frequency, a first relay, an oscillatory-cit cuit' normally operative to, maintain saidfirst; relay: in open position, means responsive to, re sonantoperation: of at least one of said vibratory elements to stop oscillations in said circuit, there by-enabling said first relay to, close, a second relay;

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
US697670A 1946-09-18 1946-09-18 Signaling system Expired - Lifetime US2485580A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
GB630815D GB630815A (de) 1946-09-18
US697670A US2485580A (en) 1946-09-18 1946-09-18 Signaling system
CH276571D CH276571A (de) 1946-09-18 1947-09-18 Signaleinrichtung.
ES0181845A ES181845A1 (es) 1946-09-18 1948-01-24 MEJORAS EN SISTEMAS DE SENALIZACIoN

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US276571XA 1946-09-18 1946-09-18
US697670A US2485580A (en) 1946-09-18 1946-09-18 Signaling system

Publications (1)

Publication Number Publication Date
US2485580A true US2485580A (en) 1949-10-25

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US697670A Expired - Lifetime US2485580A (en) 1946-09-18 1946-09-18 Signaling system

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US (1) US2485580A (de)
CH (1) CH276571A (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2584259A (en) * 1949-03-30 1952-02-05 Gen Precision Lab Inc Interoffice telephone system
US2617872A (en) * 1949-04-02 1952-11-11 Automatic Elect Lab Frequency signaling system
US3170141A (en) * 1960-12-21 1965-02-16 Standard Kollsman Ind Inc Frequency responsive interrogation system having a reply oscillator at the receiver
US3218555A (en) * 1962-12-28 1965-11-16 Gen Electric Selective calling system
US3530394A (en) * 1968-07-08 1970-09-22 Us Navy Audio frequency reject filter
US3683121A (en) * 1970-08-17 1972-08-08 Akin Aksu Indicating apparatus

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1635779A (en) * 1925-08-18 1927-07-12 Gen Electric Remote-control carrier-current system
US2131589A (en) * 1937-04-23 1938-09-27 Bell Telephone Labor Inc Signaling system
US2325829A (en) * 1940-06-10 1943-08-03 Lorain County Radio Corp Signaling system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1635779A (en) * 1925-08-18 1927-07-12 Gen Electric Remote-control carrier-current system
US2131589A (en) * 1937-04-23 1938-09-27 Bell Telephone Labor Inc Signaling system
US2325829A (en) * 1940-06-10 1943-08-03 Lorain County Radio Corp Signaling system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2584259A (en) * 1949-03-30 1952-02-05 Gen Precision Lab Inc Interoffice telephone system
US2617872A (en) * 1949-04-02 1952-11-11 Automatic Elect Lab Frequency signaling system
US3170141A (en) * 1960-12-21 1965-02-16 Standard Kollsman Ind Inc Frequency responsive interrogation system having a reply oscillator at the receiver
US3218555A (en) * 1962-12-28 1965-11-16 Gen Electric Selective calling system
US3530394A (en) * 1968-07-08 1970-09-22 Us Navy Audio frequency reject filter
US3683121A (en) * 1970-08-17 1972-08-08 Akin Aksu Indicating apparatus

Also Published As

Publication number Publication date
CH276571A (de) 1951-07-15

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