GB2375868A

GB2375868A - Alarm providing speech indication to differentiate between a test and an alarm condition of the system

Info

Publication number: GB2375868A
Application number: GB0106935A
Authority: GB
Inventors: Fariz Khellaf
Original assignee: Cooper Lighting and Security Ltd
Current assignee: Eaton Electrical Systems Ltd
Priority date: 2001-03-20
Filing date: 2001-03-20
Publication date: 2002-11-27
Anticipated expiration: 2021-03-20
Also published as: GB2375868B; GB0106935D0

Abstract

Alarm system including one or more sounders each being operable in at least two activated states, the first activated state indicating a test of the system by an audible speech message, and a second activated state indicating an alarm in the system by an audible speech message. The sounder may be triggered by a signal consisting of one or more electrical pulses having a pulse width and a voltage level, the pulses being variable by varying at least one of the number of pulses, the pulse width and the voltage level. Speech messages may be generated at the sounder(s) or remote to the sounder(s) and may be pre-recorded.

Description

ALARM SYSTEM This invention relates to an alarm system. More particularly, it relates to a fire alarm system.

Fire alarm systems are installed in buildings and typically include one or more detectors for detecting a fire and one or more sounders for sounding an alarm.

Usually, the fire alarm system includes a central control unit to which both the detectors and sounders are connected.

In the fire emergency, the detectors detect a fire or the possibility of a fire and the sounders sound the alarm to indicate this fact to occupants of the building.

The alarm sounded is typically a bell or a klaxon.

In order to ensure that, in the case of a real fire, the fire alarm system in a building functions satisfactorily, it is necessary to test the system periodically. However, testing the fire alarm system can give the impression to occupants of the building that the alarm is genuine, i. e. that there is a fire in the building. Clearly, this is undesirable.

Accordingly, the present invention provides, in the first aspect, an alarm system, including a sounder, the sounder being operable in at least two activated states, the first activated state indicating a test of the system by an audible speech message, and a second activated state indicating an alarm in the system by an audible speech message. The system therefore allows for an

audible distinction between a genuine alarm and a test of the alarm.

Typically, the speech messages are generated synthetically. That is, typically, the speech messages are not a recording of a human voice, but the speech is generated electronically by, for example, a voice chip.

Advantageously, the speech messages are synthesised in situ. For example, the speech messages may be synthesised at the location of the sounder. In such a case, a voice chip may be fitted in the sounder.

Additionally or alternatively, the speech messages may be pre-recorded on a recording medium. Preferably, the recording medium is located in the sounder.

Alternatively, the recording medium may be located remote from the sounder, for example in a control unit.

In the case where a recording medium is used, the recording medium is preferably a solid state recording medium.

Preferably the sounder is triggered to a particular activated state by a particular signal. More preferably, the signal is electrical and consists of one of: one or more electrical pulses having a pulse width; and a voltage level, and is variable by varying at least one, two or all of: the number of pulses; the pulse width ; and the voltage level.

Preferably, the alarm system is a fire alarm, the first activated state indicating a fire alarm test and the second activated state indicating a fire. More preferably, the system includes a plurality of sounders.

In a second aspect, the present invention provides a method of operating an alarm system, including the steps of: detecting a first state indicating a test of the system or a second state indicating an alarm in the system, and activating a sounder to indicate the first state or the second state, by an appropriate audible speech message.

Preferably, the alarm system operated in the second aspect of the invention includes any of the features referred to with respect to the alarm system of the first aspect.

Preferably, the method includes the step of triggering the sounder to a particular activated state by sending a particular signal to the sounder. More preferably, the signal is electrical and consists of one or more of: one or more electrical pulses having a pulse width; and a voltage level, the method preferably including the step of varying the signal to trigger the sounder by varying at least one, two or all of:

the number of pulses; the pulse width; and the voltage level.

Preferred embodiments of the invention will now be described, by way of example only.

A fire alarm system in a building has detectors to detect a fire or the possibility of a fire in the building. The detectors are electrically connected to a central control unit. The central control unit monitors the detectors.

To ensure that the sounders and/or the alarm system function satisfactorily at a particular time, the central control unit sends an electrical signal to the sounders.

This electrical signal causes the sounders to emit a sound to indicate to the occupants of the building that the system is being tested. When emitting this first sound, the sounders are in a first activated state.

In the event of a detector detecting a fire or the possibility of a fire, the central control unit sends another electrical signal to the sounders to cause the sounders to emit a different sound to indicate to the occupants of the building that there is a fire in the building. When emitting this second sound, the sounders are in a second activated state.

The sounds emitted by the sounders are pre-recorded speech sounds which are synthesised by a voice chip in the sounder, for example. Therefore, the first sound is

a first message which says,"THIS IS A TEST", for example, and the second sound is a second message,"THIS IS A REAL FIRE ALARM", for example.

By"voice chip", what is meant is an electronic device, typically including an integrated circuit, which is capable of synthesising data which, when output through an appropriate means such as a loudspeaker, sounds like human speech. The voice chip does not merely output pre-recorded human speech but synthesises speech artificially in response to particular instructions.

Alternatively, the speech sounds are pre-recorded messages consisting of a recording of a human voice or voices.

In a first embodiment, the first and second messages are synthesised by a voice chip which is located in a sounder. The voice chip in each sounder produces appropriate messages when instructed to do so by a signal from the central control unit.

The sounders are triggered by electrical signals from the central control unit. The triggering may be, for example, either by a particular number of electrical pulses, by a particular pulse width, or alternatively by a particular voltage level.

In a second embodiment, the first and second messages are synthesised by a voice chip located in the central control unit. In the event that the central control unit instructs the sounders to sound one of the

messages, this is done by the central control unit sending data in the form of an electrical signal to the sounders. The sounders then interpret the data and relay the message.

These embodiments have been described by way of example only. Modifications of these embodiments will be obvious to the person skilled in the art. Such modifications are within the scope of the invention.

Claims

CLAIMS: 1. An alarm system, including a sounder, the sounder being operable in at least two activated states, the first activated state indicating a test of the system by an audible speech message, and a second activated state indicating an alarm in the system by an audible speech message.
2. An alarm system according to Claim 1 wherein the sounder is triggered to a particular activated state by a particular signal.
3. An alarm system according to Claim 2 wherein the signal is electrical and consists of one of: one or more electrical pulses having a pulse width; and, a voltage level; and is variable by varying at least one, two or all of: the number of pulses ; the pulse width; and, the voltage level.
4. An alarm system according to any preceding claim wherein the speech messages are generated synthetically.
5. An alarm system according to claim 4 wherein the speech messages are synthesised at the location of the sounder.

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6. An alarm system according to any preceding claim wherein the speech messages are pre-recorded on a recording medium.
7. An alarm system according to Claim 6 wherein the recording medium is located in the sounder.
8. An alarm system according to Claim 6 wherein the recording medium is located remote from the sounder.
9. An alarm system according to any of claims 6 to 8 wherein the recording medium is a solid state recording medium.
10. An alarm system according to any preceding claim wherein the alarm system is a fire alarm, the first activated state indicating a fire alarm test and the second activated state indicating a fire.
11. An alarm system according to any preceding claim wherein the system includes a plurality of sounders.
12. A method of operating an alarm system, including the steps of: detecting a first state indicating a test of the system or a second state indicating an alarm in the system, and activating a sounder to indicate the first state or the second state, by an appropriate audible speech message.

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13. A method according to Claim 12 wherein the method includes the step of triggering the sounder to a particular activated state by sending a particular signal to the sounder.
14. A method according to Claim 13 wherein the signal is electrical and consists of one or more of: one or more electrical pulses having a pulse width; and, a voltage level; the method including the step of varying the signal to trigger the sounder by varying at least one, two or all of: the number of pul'ses ; the pulse width; and the voltage level.
15. An alarm system substantially as described in any one embodiment hereinbefore.
16. A method of operating an alarm system substantially as described in any one embodiment hereinbefore.