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FR2446519A1 - Telephone line signalling system - normally applies high frequency signal to line which decreases on actuation and is fed to loudspeaker and preselected station - Google Patents

Telephone line signalling system - normally applies high frequency signal to line which decreases on actuation and is fed to loudspeaker and preselected station

Info

Publication number
FR2446519A1
FR2446519A1 FR7900635A FR7900635A FR2446519A1 FR 2446519 A1 FR2446519 A1 FR 2446519A1 FR 7900635 A FR7900635 A FR 7900635A FR 7900635 A FR7900635 A FR 7900635A FR 2446519 A1 FR2446519 A1 FR 2446519A1
Authority
FR
France
Prior art keywords
line
switch
loudspeaker
fed
oscillator
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.)
Granted
Application number
FR7900635A
Other languages
French (fr)
Other versions
FR2446519B1 (en
Inventor
Henri Butin
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.)
Thales SA
Original Assignee
Thomson CSF SA
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 Thomson CSF SA filed Critical Thomson CSF SA
Priority to FR7900635A priority Critical patent/FR2446519A1/en
Publication of FR2446519A1 publication Critical patent/FR2446519A1/en
Application granted granted Critical
Publication of FR2446519B1 publication Critical patent/FR2446519B1/fr
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
    • H04M11/04—Telephonic communication systems specially adapted for combination with other electrical systems with alarm systems, e.g. fire, police or burglar alarm systems

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Devices For Supply Of Signal Current (AREA)

Abstract

The signalling system for a subscriber telephone line comprises a power supply unit (3) connected across the subscriber line wires (1, 2) and supplying an oscillator (5). The oscillator is coupled through a normally closed switch (10) to a series capacitor (11) and an inductance (12) circuit connected to one of the line wires (1), an also through a second normally open switch (9) to a loudspeaker (8). The oscillator (5) normally applies a hf signal of e.g. 9 KHz to the line through the first switch. The two switches are gauged with a third switch (14) and controlled by a control switch (13). Under normal circumstances, the 9 KHz is detected by a receiver on the line. If the subscriber actuates the control switch, the switch (10) opens and the switch (14) closes to lower the oscillator frequency which is fed to the loudspeaker. Simultaneously the receiver detects the absence of the 9 KHz signal and automatically notifies a preselected line terminal.
FR7900635A 1979-01-11 1979-01-11 Telephone line signalling system - normally applies high frequency signal to line which decreases on actuation and is fed to loudspeaker and preselected station Granted FR2446519A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR7900635A FR2446519A1 (en) 1979-01-11 1979-01-11 Telephone line signalling system - normally applies high frequency signal to line which decreases on actuation and is fed to loudspeaker and preselected station

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7900635A FR2446519A1 (en) 1979-01-11 1979-01-11 Telephone line signalling system - normally applies high frequency signal to line which decreases on actuation and is fed to loudspeaker and preselected station

Publications (2)

Publication Number Publication Date
FR2446519A1 true FR2446519A1 (en) 1980-08-08
FR2446519B1 FR2446519B1 (en) 1982-02-05

Family

ID=9220633

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7900635A Granted FR2446519A1 (en) 1979-01-11 1979-01-11 Telephone line signalling system - normally applies high frequency signal to line which decreases on actuation and is fed to loudspeaker and preselected station

Country Status (1)

Country Link
FR (1) FR2446519A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2499737A1 (en) * 1981-02-12 1982-08-13 Laudren Cie Sa Ets M ALARM CIRCUIT FOR SURVEILLANCE SYSTEMS FOR PUBLIC TELEPHONE POSITIONS IN PREPAID

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2911474A (en) * 1957-11-01 1959-11-03 Bell Telephone Labor Inc Telephone alarm system
FR1559686A (en) * 1966-12-12 1969-03-14
US3789382A (en) * 1972-08-11 1974-01-29 Centralalarm Int Inc Alarm system with central station monitoring of key operated locks of a number of remote stations
DE2424588A1 (en) * 1974-05-21 1975-12-04 Merk Gmbh Telefonbau Fried Alarm circuit with frequency generator - supplies separate characteristic frequencies to central control
DE2722377A1 (en) * 1977-05-17 1978-11-30 Siemens Ag Telephone exchange using subscriber station as alarm station - interrupts AF signal in case of alarm and connects station to reporting point

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2911474A (en) * 1957-11-01 1959-11-03 Bell Telephone Labor Inc Telephone alarm system
FR1559686A (en) * 1966-12-12 1969-03-14
US3789382A (en) * 1972-08-11 1974-01-29 Centralalarm Int Inc Alarm system with central station monitoring of key operated locks of a number of remote stations
DE2424588A1 (en) * 1974-05-21 1975-12-04 Merk Gmbh Telefonbau Fried Alarm circuit with frequency generator - supplies separate characteristic frequencies to central control
DE2722377A1 (en) * 1977-05-17 1978-11-30 Siemens Ag Telephone exchange using subscriber station as alarm station - interrupts AF signal in case of alarm and connects station to reporting point

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2499737A1 (en) * 1981-02-12 1982-08-13 Laudren Cie Sa Ets M ALARM CIRCUIT FOR SURVEILLANCE SYSTEMS FOR PUBLIC TELEPHONE POSITIONS IN PREPAID
EP0058600A1 (en) * 1981-02-12 1982-08-25 Etablissements M. LAUDREN & Compagnie S.A. Alarm circuit for public prepayment telephone station monitoring system

Also Published As

Publication number Publication date
FR2446519B1 (en) 1982-02-05

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Legal Events

Date Code Title Description
ST Notification of lapse