FR2362456A1 - Centralised supervisory and alarm system for remote subscriber units - uses three signal transmission system to detect and verify correct alarm condition - Google Patents
Centralised supervisory and alarm system for remote subscriber units - uses three signal transmission system to detect and verify correct alarm conditionInfo
- Publication number
- FR2362456A1 FR2362456A1 FR7625233A FR7625233A FR2362456A1 FR 2362456 A1 FR2362456 A1 FR 2362456A1 FR 7625233 A FR7625233 A FR 7625233A FR 7625233 A FR7625233 A FR 7625233A FR 2362456 A1 FR2362456 A1 FR 2362456A1
- Authority
- FR
- France
- Prior art keywords
- signals
- supervisory
- central
- signal transmission
- transformer
- 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
Links
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
- G08B29/02—Monitoring continuously signalling or alarm systems
- G08B29/06—Monitoring of the line circuits, e.g. signalling of line faults
- G08B29/08—Signalling of tampering with the line circuit
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
- G08B25/01—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium
- G08B25/08—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium using communication transmission lines
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Computer Security & Cryptography (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Alarm Systems (AREA)
Abstract
The supervisory and alarm system controls from a central post a number of remote installations via signals transmitted over telephone wires. Interruption of a signal during a predetermined time period actuates an alaram. The time also transmits during this period a succession of irregular signals which are designed to counteract fraudulent recorded signal transmission. In the central supervisory unit there is a section for each subscriber on which is mounted a differential transformer. Through this transformer to the subscriber circuits are applied signals from the incoming line. The transformer also introduces into the circuits the succession of irregular signals emanating from a central source. The differential transformer ensures during processing of the output signals that the effect of irregular signals from the central source are minimised. The subscriber circuits in the central unit have an amplifier with automatic gain control amplifying the frequency of the irregular signals.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR7625233A FR2362456A1 (en) | 1976-08-19 | 1976-08-19 | Centralised supervisory and alarm system for remote subscriber units - uses three signal transmission system to detect and verify correct alarm condition |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR7625233A FR2362456A1 (en) | 1976-08-19 | 1976-08-19 | Centralised supervisory and alarm system for remote subscriber units - uses three signal transmission system to detect and verify correct alarm condition |
Publications (2)
Publication Number | Publication Date |
---|---|
FR2362456A1 true FR2362456A1 (en) | 1978-03-17 |
FR2362456B1 FR2362456B1 (en) | 1982-08-20 |
Family
ID=9177010
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
FR7625233A Granted FR2362456A1 (en) | 1976-08-19 | 1976-08-19 | Centralised supervisory and alarm system for remote subscriber units - uses three signal transmission system to detect and verify correct alarm condition |
Country Status (1)
Country | Link |
---|---|
FR (1) | FR2362456A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2551280A1 (en) * | 1983-08-25 | 1985-03-01 | Gotanda Motohiro | BUILDING MONITORING DEVICE |
-
1976
- 1976-08-19 FR FR7625233A patent/FR2362456A1/en active Granted
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2551280A1 (en) * | 1983-08-25 | 1985-03-01 | Gotanda Motohiro | BUILDING MONITORING DEVICE |
Also Published As
Publication number | Publication date |
---|---|
FR2362456B1 (en) | 1982-08-20 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
ST | Notification of lapse |