US2263139A - Carrier signaling system - Google Patents

Carrier signaling system Download PDF

Info

Publication number
US2263139A
US2263139A US322402A US32240240A US2263139A US 2263139 A US2263139 A US 2263139A US 322402 A US322402 A US 322402A US 32240240 A US32240240 A US 32240240A US 2263139 A US2263139 A US 2263139A
Authority
US
United States
Prior art keywords
line
rectifiers
relay
carrier
circuit
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
US322402A
Other languages
English (en)
Inventor
Parker John Ernest Thomas
Mccusker Joseph Bernard
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.)
Automatic Telephone and Electric Co Ltd
Original Assignee
Automatic Telephone and Electric Co Ltd
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
Application filed by Automatic Telephone and Electric Co Ltd filed Critical Automatic Telephone and Electric Co Ltd
Application granted granted Critical
Publication of US2263139A publication Critical patent/US2263139A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q5/00—Selecting arrangements wherein two or more subscriber stations are connected by the same line to the exchange
    • H04Q5/02—Selecting arrangements wherein two or more subscriber stations are connected by the same line to the exchange with direct connection for all subscribers, i.e. party-line systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/46—Monitoring; Testing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J1/00—Frequency-division multiplex systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J1/00—Frequency-division multiplex systems
    • H04J1/02—Details
    • H04J1/14—Arrangements providing for calling or supervisory signals
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M7/00—Arrangements for interconnection between switching centres
    • H04M7/16—Arrangements for interconnection between switching centres in systems employing carrier frequencies
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H04Q1/30—Signalling arrangements; Manipulation of signalling currents
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q1/00—Details of selecting apparatus or arrangements
    • H04Q1/18—Electrical details
    • H04Q1/30—Signalling arrangements; Manipulation of signalling currents
    • H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
    • H04Q1/442—Signalling arrangements; Manipulation of signalling currents using alternate current with out-of-voice band signalling frequencies
    • H04Q1/4423—Signalling arrangements; Manipulation of signalling currents using alternate current with out-of-voice band signalling frequencies using one signalling frequency

Definitions

  • the main object of theinvention is to provide a simple and improved selective ringing scheme for use on systems of the above described-type.
  • a'telephone system having a carrier frequency-channel and an audio frequency channel superimposed on the same line in which the signaling for one channel is effected by causing direct current to flow over the line while signaling for the other channel is effected by causing alternating current to flow over the line.
  • Each terminal equipment includes a combined modulator and demodulator unit or so-called mod'em MD which operates in conjunction with a single valve carrier frequency generator OSC, generating anfrequency of the order of 6.5 kilocycles.
  • mod'em MD which operates in conjunction with a single valve carrier frequency generator OSC, generating anfrequency of the order of 6.5 kilocycles.
  • the arrangements are moreover such that the lower side-band frequency is used for and will be known.
  • leads l4 and I5 on the right hand side of the drawing connect up overthe-carrier exchangeline conductors 10, ll, they extend via the low pass filters LPFI having a;pass rangeupto'3000 cycles, and thence via th'e modem'input transformer TI to the modem which is of the fully balanced carriersuppressing-type and employing metal rectifiers MRE-MRH.
  • a carrier frequency of the ordero'f 6-55- k-ilocycles is applied thereto from the oscillator OSC via-the transformer T3, the oscillator comprising vavalve .Vl connected up in an oscillatorycircuit, power to the valve Vl being assumed to'be provided from the 50 volt supply serving the-whole-equipment. although if desired a high voltagemainssupplycouldi be utilised for thepurpose.
  • the oscillatory circuit comprises the primary of the transformer T4, the fixed condenser QEand variable condenser QD.
  • the circuit is connected to the anode of VI over a condenser QB.
  • the carrier frequency is suppressed in the modem and the outputfrom' the transformer T2 will inthe main consist of upper and lower sideband frequencies.
  • the secondary windings of this transformer are connected to a low pass filter LPE2 having a passrange up to 6,350 cycles, and hence it will offer a block to the upper sideband frequencies, whilethe lower side-band frequencies will be able to pass through and thence via'the high pass filter HPF, having a pass range At the distant end the received lower sideband will extend viaa high pass filter and low pass filter corresponding to HPF and LPF2 and thence into themodem unit where demodulation with the line to a distant exchange, the line being either an open line or an unloaded cable line not exceeding 10 db attenuation.
  • the operations will :be identical except that the modem unit shown-will operate as a demodulator to lower side-bandl' frequencies received over leads l4, l5 and will extend audio frequencies via transformer TLand filter LPFI back on to the carrier exchange line conductors 1.0, II,
  • the speech currents will extend via the low pass filter LPF3, on to the outgoing line conductors l4 and I5, and in this instance the high pass filter HP]? will prevent the feeding back of these frequencies into the modem MD.
  • the received audio frequencies are pilotedthrough' a low pass filter corresponding to LPF3 and thence to the receiving subscriber, a high pass filter corresponding to HPF preventing these frequencies from..feeding into the distant modem unit.
  • relay R shownas a standard ,direct current relay connected in circuit with a rectifier bridge comprising rectifiers MRA-MRD, but which might be an alternating current relay.
  • a resistance YE is inserted in one of the leads to the rectifierbridge as shown.
  • Relay R in operating at its armatures T2 and r3 connects up the earthed positivepole of the battery via rectifiers MRL. and MRM through the windings of relay M onto the 1ine;conductors IA, l5.
  • relay M In, operating operates a relay C and starts up the distant ringing generator which is maintained in operation by relay C which applies ringing current to the distant.oarriergexchange line.
  • relay C At the originating end relay C is prevented from operating on the operation .of relay M owing to the opening of its circuit by the operated armature rl.
  • the simplex'direct current signal received over leads, I4 and I5 operates relay M which willbe connected to negative battery via rectifiers MRK and MRJ andzthisrelay at armature ml earths lead I6 to start up the ringing generator and at armature m2. completes a circuit to relay C which is slightly slow in operating to give immunity from false operation to line clicks and surges.
  • Relay C-in operating maintains an earth on lead l6 over cl, disconnects'the circuit of relay R and connects'up the ringing generator GNRover contactscZ, 03 so as to return a ringing; signal back over the carrier exchange line conductor;l.0,;ll. .i
  • ringing current for the audio circuit in conjunction with direct current for the carrier current channel as far as the line is concerned enables the two circuits to be operated with no interference therebetween either from the signaling or transmission point of view.
  • the ringing current utilised for signaling over the audio circuit is prevented from feeding back into the carrier equipments at each end of the line due to the blocking effect of the 3,900 cycle high pass filters, while the carrier channel D.
  • C. signaling relays M are entirely unresponsive to ringing current, since this current will flow through each of the relays with the windings in series opposition, and furthermore the pair of rectifiers in series with each relay will be in opposing directions of conductivity as far as loop circuit signaling is concerned.
  • the rectifiers also function during conversation over the line either on the audio circuit or carrier channel to oi fer a high impedance at the low value speech voltages so that even though the relays are connected across the lines with their windings in oppositionand are therefore to all intents and purposes non-inductive, the rectifiers in series therewith, will ofi-er such impedance as to reduce transmission losses to negligible proportions.
  • the D. C. signaling relays M on the line are normally connected to earth through their batteries and any difference in the battery voltage or earth potential at the two exchanges may cause a circulating current to flow which will bring about false operation, but this is prevented by virtue of the rectifiers connected in circuit therewith, since the pair of rectifiers at one end of the line is connected up in an opposing direction. to that at the other end of the line during such times as the relay R at either end is normal.
  • Facilities are provided for synchronising the carrier frequencies between the local and distant stations, and. this is effected by inserting into the jack JL in each terminating equipment a plug having a telephone instrument connected thereto.
  • carrier current will be transmitted to line at both ends thereof, and if a beat frequency is heard, the frequency of the carrier frequency generator in the local and/or distant terminating equipment will be varied by means of the variable condenser QD until it disappears, when both carrier sources will be in synchronism with one another.
  • a resistance YB is inserted in one of the leads to the jack. Jack JE simply serves for monitoring purposes on the carrier channel.
  • the various filtersprovided in the terminating equipments may be of a very simple type as their only function is to separate the carrier channel from the audio cir cult and vice Versa during signaling and. con versation.
  • a line a path connected to said line including a low pass filter to permit the passage of low frequency alternating current for signaling purposes to both conductors of saidline inaseries circuit as well as speech currents, a second pathnon-conductive to direct currents connected to said'line and including a highpass'filter to permitthe passage of carrier frequency alternating currents to said line, and means for causing direct current to flow over said line for signaling purposes in connection with signals-are-to be extended over a common line saidcarrier frequency currents only.
  • a line a path connected tosaid line of such a nature as to permit the passage of lowfrequency alternating current for signalingpurposes to both conductors of said line in a series circuit, a second path connected across said lineincluding a relay and two rectifiers connected in opposite senses so as to offer a high impedance at all times to alternating current potentials between the conductors of said line, and means for connecting a pole of a direct current source to a point between said rectifiers to permit the passage of direct current to the two conductors of said line in parallel.
  • a line In a telephone system, a line, a path connected to said line of such a nature as to permit the passage of low frequency alternating current for signaling purposes to both conductors of said line in a series circuit, a second path across said line including both windings of a double-wound relay and a pair of rectifiers in series therewith between saidwindings and offering a high impedance to alternating current, and means for connecting a pole of a direct current source to a point between said rectifiers to permit the passage of direct current to the two conductors of said line in parallel.
  • a line a path connected to said line of such a nature as to permit the passage of low frequency alternating current for signaling purposes to both conductors of said line in a series circuit, a second circuit across saidline including both windings of a double-wound relay, switching means, a pair of rectifiers connected in opposition so as to offer a high impedance to alternating current potentials across said line, a second pair of rectifiers also connected in opposition to each other and in opposite directions to said first pair and arranged to replace said first pair when the switching means are operated, and a direct current source having one pole connected to the intermediate point of said first pair of rectifiers and the other pole connected to the intermediate point of said second pair of rectifiers so as to permit current to flow in opposite directions through the windings of said relay according as to whether said switching means are operated or not.
  • a line a path connected to said line including a low pass filter to permit the passage of low frequency alternating current for signaling purposes to said line as Well as speech currents, a second path non-conductive to direct currents connected to said line and including a high pass filter to permit the passage of carrier frequency alternating currents to said line, means for causing direct current to flow over said line for signaling purposes in connection with said carrier frequency currents including a relay and two rectifiers connected in opposite senses so as to oifer a high impedance at all times to alternating current potentials betweenthe conductors of said line, and means for connecting a pole of a directcurrent-source to ajpointbetween said rectifiers to permit the passage of direct current to the two conductors of said line in parallel.
  • a line a path connected to said line including a low pass filter to permit the passage of low frequency alternating current for signaling purposes to said line as well as speech currents, a second path non-conductive to direct currents connected to said line and including.
  • a high pass filter to permit the passage of carrier frequency alternating currents to said line, and means for causing direct current to fiow over said line for signaling purposes in connection with said carrier frequency currents including both windings of a double-wound relay, switching means, a pair of rectifiers connected in opposition so as to offer a high impedance to alternating current potential across said line, a second pair of rectifiers also connected in opposition to each other and in opposite directions to said first pair and arranged to replace said first pair when the switching means are operated, and a direct current source having one pole connected to the intermediate point of said first pair of rectifiers and the other pole connected to the intermediate point of said second pair of rectifiers so as to permit current to flow in opposite directions according to whether said switching means are operated or not.
  • a line a circuit connected to said line of such a nature as to permit the passage of low frequency alternating current for signaling purposes to both conductors of said line in a series circuit, a second circuit connected across said line including a relay and two recti-, bombs connected in opposite senses so as to offer a high impedance at all times to alternating current potentials between'the conductors of said line, switching means for controlling the connection of a pole of a direct current source and said rectifiers to permit the passage of direct current to the two conductors of said line in parallel, and an alternating current relay device for effecting the operation of said switching means.
  • a line a circuit connected to said line of such a nature as to permit the passage of low frequency alternating current for signaling purposes to bothconductors of said line in a series circuit, a second circuit across said line including both windings of a double-wound relay and a pair of rectifiers in series therewith between said windings and offering a high impedance to alternating current, means for connecting a pole of a direct current source to a to both conductors of said line in a series circuit, a, second path non-conductive to direct currents and including a high pass filter to permit the passage of carrier frequency alternating currents to said line, a third path including both windings of a double-wound relay and a pair of rectifiers in series therewith between said windings and ofiering a high impedance to alternating current, and a direct current source having one pole connected to a point between said rectifiers to permit the passage of direct current to the two conductors of said line in parallel, said third path serving
  • a line a path connected to said line of such a nature as to permit the passage of low frequency alternating current for signaling purposes as well as speech currents to both conductors of said line in a series circuit, a second path non-conductive to direct currents and including a speech current receiving circuit, a six termina1 modulator-demodulator unit and a high pass filter to permit the passage of carrier frequency alternating currents modulated by speech currents received by said speech receiving circuit to said line, a third path including both windings of a double circuit relay, switching means, a pair of rectifiers connected in opposition so as to offer a high impedance to alternating current potentials across said line, a second pair of rectifiers also connected in opposition to each other and in opposite directions to said first pair and arranged to replace said first pair when the switching means are operated, a direct current source having one pole connected to the intermediate point of said first pair of rectifiers and the other pole connected to the intermediate point of said second pair of rectifiers, and an alternating current device associated with said

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Devices For Supply Of Signal Current (AREA)
US322402A 1939-04-26 1940-03-05 Carrier signaling system Expired - Lifetime US2263139A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2263139X 1939-04-26

Publications (1)

Publication Number Publication Date
US2263139A true US2263139A (en) 1941-11-18

Family

ID=10902543

Family Applications (1)

Application Number Title Priority Date Filing Date
US322402A Expired - Lifetime US2263139A (en) 1939-04-26 1940-03-05 Carrier signaling system

Country Status (4)

Country Link
US (1) US2263139A (fr)
BE (1) BE466943A (fr)
FR (1) FR931904A (fr)
NL (1) NL65711C (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2596977A (en) * 1947-10-08 1952-05-20 Int Standard Electric Corp Ringing equipment

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2596977A (en) * 1947-10-08 1952-05-20 Int Standard Electric Corp Ringing equipment

Also Published As

Publication number Publication date
FR931904A (fr) 1948-03-08
NL65711C (fr)
BE466943A (fr)

Similar Documents

Publication Publication Date Title
US2263139A (en) Carrier signaling system
US2344634A (en) Telephone intercept system
US2552780A (en) Two-way loop and earth current signaling system
US2308637A (en) Telephone system
US2031692A (en) Telephone system
US2214213A (en) Telephone system
US2306173A (en) Telephone system
US3033932A (en) Selective ringing multi-party telephone system
US2503011A (en) Rectifier arrangement for switching purposes
US2590746A (en) Control system for carrier telecommunication circuits
US2315378A (en) Automatic telephone system
US1919046A (en) Selective calling circuits
US2367518A (en) Signaling system
US2145095A (en) Telephone system
US1480235A (en) Carrier-wave signaling system
US2366854A (en) Electric impulse signaling system
US1778768A (en) Telephone-ringing system
US2594718A (en) Supervisory signaling circuits for carrier wave communication systems and the like
US1896315A (en) Telephone system
US2748193A (en) Duplex signaling system
US2511616A (en) Power line carrier frequency telephone system
US1737423A (en) Automatic telephone system
US2238469A (en) Signaling system
US2461200A (en) Automatic line voltage compensator and impulse repeater for signaling systems
US1610234A (en) Carrier-signaling system