GB541731A - Improvements in and relating to telephone and like systems - Google Patents

Improvements in and relating to telephone and like systems

Info

Publication number
GB541731A
GB541731A GB9983/40A GB998340A GB541731A GB 541731 A GB541731 A GB 541731A GB 9983/40 A GB9983/40 A GB 9983/40A GB 998340 A GB998340 A GB 998340A GB 541731 A GB541731 A GB 541731A
Authority
GB
United Kingdom
Prior art keywords
signals
voice
relay
circuit
frequency
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
Application number
GB9983/40A
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.)
Telephone Manufacturing Co Ltd
Original Assignee
Telephone Manufacturing 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 Telephone Manufacturing Co Ltd filed Critical Telephone Manufacturing Co Ltd
Priority to GB9983/40A priority Critical patent/GB541731A/en
Priority to US397463A priority patent/US2290570A/en
Publication of GB541731A publication Critical patent/GB541731A/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
    • H04Q1/446—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using one signalling frequency
    • H04Q1/4465—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using one signalling frequency the same frequency being used for all signalling information, e.g. A.C. nr.9 system

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Devices For Supply Of Signal Current (AREA)

Abstract

541,731. Voice-frequency receivers. TELEPHONE MANUFACTURING CO., Ltd., and PADDLE, L. H. June 7, 1940, No. 9983. [Class 40 (iv)] [Also in Group XL] In a telephone system a relay circuit which functions to distinguish between calling or ringing signals and fortuitous voice frequency signals comprises a transformer T1 which serves to feed modulated carrier wave signals to the control grid of a valve V the amplified output of which is taken from the screen grid and applied through a tuned transformer T2 to a rectifier network D1 which feeds the modulation component back to the control grid. The output circuit from the anode includes an inductance L1 the voltage across which is rectified at D2 for operating relay RL. By adjusting resistance R2 the relay may be made to respond only to steep-fronted signals and not to fortuitous voice signals. In a modification, the output circuit from the first rectifier is tuned to the modulation frequency so as to be more selective. In a further modification, amplitude-limiting means are provided at the input of the circuit. Specification 539,595 is referred to in the Provisional Specification.
GB9983/40A 1940-06-07 1940-06-07 Improvements in and relating to telephone and like systems Expired GB541731A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB9983/40A GB541731A (en) 1940-06-07 1940-06-07 Improvements in and relating to telephone and like systems
US397463A US2290570A (en) 1940-06-07 1941-06-10 Telephone and like system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9983/40A GB541731A (en) 1940-06-07 1940-06-07 Improvements in and relating to telephone and like systems

Publications (1)

Publication Number Publication Date
GB541731A true GB541731A (en) 1941-12-09

Family

ID=9882369

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9983/40A Expired GB541731A (en) 1940-06-07 1940-06-07 Improvements in and relating to telephone and like systems

Country Status (2)

Country Link
US (1) US2290570A (en)
GB (1) GB541731A (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2440049A (en) * 1945-06-30 1948-04-20 Rca Corp Electronic audio switch
US2561602A (en) * 1947-07-29 1951-07-24 Thomas J Valentino Apparatus for making aural announcements
US2681386A (en) * 1948-07-13 1954-06-15 Automatic Telephone & Elect Electrical signaling system using nonlinear resistors for control
NL159620C (en) * 1950-03-08
BE501904A (en) * 1950-03-17
US3124658A (en) * 1958-02-28 1964-03-10 Input

Also Published As

Publication number Publication date
US2290570A (en) 1942-07-21

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