GB1494893A - Alarm signalling systems - Google Patents

Alarm signalling systems

Info

Publication number
GB1494893A
GB1494893A GB4701573A GB4701573A GB1494893A GB 1494893 A GB1494893 A GB 1494893A GB 4701573 A GB4701573 A GB 4701573A GB 4701573 A GB4701573 A GB 4701573A GB 1494893 A GB1494893 A GB 1494893A
Authority
GB
United Kingdom
Prior art keywords
fault
alarm
premises
station
central station
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
GB4701573A
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.)
EMI Ltd
Original Assignee
EMI 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 EMI Ltd filed Critical EMI Ltd
Priority to GB4701573A priority Critical patent/GB1494893A/en
Publication of GB1494893A publication Critical patent/GB1494893A/en
Expired legal-status Critical Current

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
    • G08B29/12—Checking intermittently signalling or alarm systems
    • 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
    • G08B25/009—Signalling of the alarm condition to a substation whose identity is signalled to a central station, e.g. relaying alarm signals in order to extend communication range
    • 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

Abstract

1494893 Alarm signalling system EMI Ltd 7 Jan 1975 [9 Oct 1973] 47015/73 Heading G4H An alarm signalling system comprises protected premises 1a-1e connected to collector stations 5, 6 which are connected in turn to a central station 7. Each of the premises 1 contains a control unit 2a associated with a fire (or intruder) sensor and a transmitter 3a. Each collector station contains a multiplex receiver 5a or 6a, 6c and a multiplex transmitter 5b or 6b. The central station contains a receiver 8, a control unit 9, fault and system state displays 13, 10 an alarm unit 11 and a fault alarm 12. Four types of signal are transmitted over post office cables 4a or 4b: normal, alarm, alarm test and control unit fault (Fig. 3, not shown). Premises 1 normally transmits an 800 Hz signal with a 10 Hz modulation, which causes station 5 to transmit back a 2À1 kHz signal with a 10 Hz modulation. An alarm removes the modulation, a fault changes the 800 Hz frequency to 400 Hz, and a test does both, similar changes being caused in the retransmitted signal or by a fault in station 5; these signals operate appropriate lamps and a buzzer. The collector stations are connected to each other and to the central station by post office cables 4c, 4d and contain appropriate multiplexing circuitry (Fig. 4, not shown). Data transfer is by means of frequency shift keying using two frequencies with a bandwidth restriction to allow for frequency division multiplex if necessary. In the central station, display 10 displays system state conditions for up to 100 premises: red and amber lights indicate fire and fault conditions respectively, and both lights indicate a test condition; a change of state is indicated by a flashing light. Display 13 displays up to 100 fault signals; units 11 and 12 provide change of state indications and may include audible indicators.
GB4701573A 1973-10-09 1973-10-09 Alarm signalling systems Expired GB1494893A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB4701573A GB1494893A (en) 1973-10-09 1973-10-09 Alarm signalling systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB4701573A GB1494893A (en) 1973-10-09 1973-10-09 Alarm signalling systems

Publications (1)

Publication Number Publication Date
GB1494893A true GB1494893A (en) 1977-12-14

Family

ID=10443404

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4701573A Expired GB1494893A (en) 1973-10-09 1973-10-09 Alarm signalling systems

Country Status (1)

Country Link
GB (1) GB1494893A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0039203A2 (en) * 1980-04-26 1981-11-04 The City of Edinburgh District Council Sheltered housing schemes communications system
FR2506480A1 (en) * 1981-05-25 1982-11-26 Signalisation Continental Call transmission arrangement e.g. for elderly - uses radiating network with telephone lines radio links and local two-wire connections for monitored terminals
EP0294532A1 (en) * 1986-04-11 1988-12-14 ADT, Inc. Integrity securing monitor and method for a security installation
GB2484867B (en) * 2009-08-14 2016-03-02 Tyco Safety Prod Canada Ltd System and method for multiport automation

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0039203A2 (en) * 1980-04-26 1981-11-04 The City of Edinburgh District Council Sheltered housing schemes communications system
EP0039203A3 (en) * 1980-04-26 1982-09-29 The City Of Edinburgh District Council Sheltered housing schemes communications system
FR2506480A1 (en) * 1981-05-25 1982-11-26 Signalisation Continental Call transmission arrangement e.g. for elderly - uses radiating network with telephone lines radio links and local two-wire connections for monitored terminals
EP0294532A1 (en) * 1986-04-11 1988-12-14 ADT, Inc. Integrity securing monitor and method for a security installation
GB2484867B (en) * 2009-08-14 2016-03-02 Tyco Safety Prod Canada Ltd System and method for multiport automation

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Legal Events

Date Code Title Description
PS Patent sealed
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PE20 Patent expired after termination of 20 years

Effective date: 19950106