US1361486A - Composite signaling system - Google Patents

Composite signaling system Download PDF

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Publication number
US1361486A
US1361486A US266326A US26632618A US1361486A US 1361486 A US1361486 A US 1361486A US 266326 A US266326 A US 266326A US 26632618 A US26632618 A US 26632618A US 1361486 A US1361486 A US 1361486A
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US
United States
Prior art keywords
telephone
telegraph
currents
circuit
signaling
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
US266326A
Other languages
English (en)
Inventor
Harold S Osborne
Ralzemond D Parker
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.)
AT&T Corp
Original Assignee
American Telephone and Telegraph Co Inc
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 American Telephone and Telegraph Co Inc filed Critical American Telephone and Telegraph Co Inc
Priority to US266326A priority Critical patent/US1361486A/en
Priority to US267527A priority patent/US1378170A/en
Priority to FR505646A priority patent/FR505646A/fr
Priority to FR21805A priority patent/FR21805E/fr
Priority to DEB94501D priority patent/DE432495C/de
Application granted granted Critical
Publication of US1361486A publication Critical patent/US1361486A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
    • H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/04—Control of transmission; Equalising
    • H04B3/14—Control of transmission; Equalising characterised by the equalising network used
    • H04B3/141—Control of transmission; Equalising characterised by the equalising network used using multiequalisers, e.g. bump, cosine, Bode

Definitions

  • This invention relates to composite signal transmitting systems such, for instance, as are used for simultaneously sending telephone and telegraph messages over the same wires. Its object is to improve the efficiency of such systems and to render such service available over circuits of certain characters where it has heretofore beenimpossible.
  • Telephone currents are of the order of one inilli-ampere while telegraph currents 'areordinarily of the order of eighty milli-amperes. It has been found that when telegraph currents of this magnitude are superimposed on high eiliciency telephone lines embodying many loading coils and the amplifiers now inuse,"tl1at the telephone current is interfered with to such an extent as to render it unlit for commercial purposes in some cases wholly unintelligible. This is particularly true of very long cable circuits in which the total number of loading coils is large and the amplifiers are operated with very large amplifications.
  • the telegraph current will come to its operating value at a comparatively slow rate and the speed of signaling is necessarily limited.
  • a metallic circuit for the combined telephone and telegraph circuit and reducing the value of the telegraph current as above indicated the danger of interference with the telephone circuit by the high frequency components of the telegraph impulses is so diminished that it is possible to use a composite set designed to pass a telegraph current wave reaching its operating value sooner than under the old system, and therefore giving increased speeds of operation without interference with the telephone conversa lion.
  • FIG. 1 is a reproduction from. an oscillograph record showing the interference of telegraph impulses with telephone currents
  • Fig. 2 shows diagramm'atically a circuit such as may be used in employing the present invention.
  • A represents a telegraph current and B the telephone current as it is affected graph lines the telephone line is provided by the loading coils in the circuit, when a telegraph current A of the magnitude heretofore used is superposed on the circuit.
  • the telephone current is here represented as of a constant frequency of 800 cycles. It will be noted that there is a diminution of telephone current each time there is a rapid change in the value of the telegraph current as at the points 00, each of these producing its well identified effect in B at points y. The results evidenced at y lag slightly behind the points of rapid change in the telegraph current as will be seen from the drawing. This diminution is known as the flutter effect on the telephone circuit and is caused by the action of the telegraph currents upon the loading coils. This effect may be so great in some cases as to practically suppress the telephone current.
  • FIG. 2, 1 represents a typical telephone circuit embodying loading coils 2 and repeaters 3.
  • a telephone set 44 for sending and receiving telephone messages
  • a telegraph apparatus, 55 for sending and receiving telegraphic signals.
  • the telephone apparatus illustrated is of a well known type and needs no detailed description.
  • the telegraph sets 6 represents the receiving relay and 7 in sending key. Each of these is in practice associated in a well known manner with the usual relays, (not shown).
  • the elements of this composite set 'located in the telegraph branch will, in accordance with this invention, be designed to permit the passage of frequencies corresponding to the increased rate of telegraph signaling which as above noted is possible with the arrangement herein described without interference with the telephone communication.
  • the windings of relay 6 are divided between the opposite sides of the circuit and are connected between the line 1 and the artificial line N.
  • the sending apparatus 7 is connected to the opposite sides of the line at the midpoints of the relay winding 6 so that impulses emanating therefrom will have no eilect upon the -re DCving relay since they divide equally and traverse in opposite directions the two halves of the winding.
  • the groupof series inductances and shunt capacities indicated at 12 serve to partially suppress the high mactsra'pidly varying components without interfe'rence with the telephone circuit.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
US266326A 1918-12-11 1918-12-11 Composite signaling system Expired - Lifetime US1361486A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US266326A US1361486A (en) 1918-12-11 1918-12-11 Composite signaling system
US267527A US1378170A (en) 1918-12-11 1918-12-19 Repeater-circuits
FR505646A FR505646A (fr) 1918-12-11 1919-11-03 Système de transmission pour des services téléphoniques et télégraphiques combinés
FR21805A FR21805E (fr) 1918-12-11 1919-11-05 Système de transmission pour des services téléphoniques et télégraphiques combinés
DEB94501D DE432495C (de) 1918-12-11 1920-06-13 Signalsystem fuer gleichzeitiges Telegraphieren und Telephonieren ueber mit Induktionsspulen ausgeruestete Leitungen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US266326A US1361486A (en) 1918-12-11 1918-12-11 Composite signaling system

Publications (1)

Publication Number Publication Date
US1361486A true US1361486A (en) 1920-12-07

Family

ID=23014110

Family Applications (1)

Application Number Title Priority Date Filing Date
US266326A Expired - Lifetime US1361486A (en) 1918-12-11 1918-12-11 Composite signaling system

Country Status (3)

Country Link
US (1) US1361486A (de)
DE (1) DE432495C (de)
FR (2) FR505646A (de)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE972640C (de) * 1952-04-10 1959-08-27 Siemens Ag Schaltungsanordnung fuer Fernmeldeanlagen zur gleichzeitigen UEbertragung von Fernsprechstroemen und Signalen ueber dieselben Leitungsadern

Also Published As

Publication number Publication date
FR505646A (fr) 1920-08-03
FR21805E (fr) 1921-03-30
DE432495C (de) 1926-08-09

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