WO2003098907A2

WO2003098907A2 - Personal alarm systems and method

Info

Publication number: WO2003098907A2
Application number: PCT/GB2003/002139
Authority: WO
Inventors: Mark Cowper; Jimmy Dripps; John Mackinnon; Aland Fraser Murray
Original assignee: The University Court Of The University Of Edinburgh
Priority date: 2002-05-22
Filing date: 2003-05-20
Publication date: 2003-11-27
Also published as: WO2003098907A3; AU2003227953A1; GB0211670D0; AU2003227953A8

Abstract

A personal alarm system is provided comprising trigger means enabled to send command and communication signals to a telephony interface unit, receive communication signals from the telephony interface unit, send prompt signals and communication signals to a user, and receive command and communication signals from the user, such that a two-way communication link can be established between the user and a remote aid source. The telephony interface can be provided as part of the marketed system. A call centre is also provided to deal with calls made from the system.

Description

Personal Alarm Systems, Method and Call Centre.

The present invention relates to systems to care for and support elderly or frail people, in particular to personal alarm systems, a method of providing a personal alarm system, and a call centre .

A way of caring for elderly or frail people is to provide them with support in their own homes. This is often preferable to accommodating them in a care home where they can be looked after continuously, as this option takes away the elderly person's independence and is expensive.

Caring for elderly or frail people in their own homes also eases the burden on the national social and medical services, especially in countries which are currently experiencing a demographic trend towards an ageing population, such as the United Kingdom . One way of caring for elderly or frail people in their own homes is to provide an alarm system and a warden or other helper who can attend to the elderly person when the alarm is activated.

Such a system typically comprises a small portable trigger, typically in the form of a neckstrap or wristband, which is worn by the elderly person. Should the elderly person require help at home, for example if they have fallen down and cannot get up again, they simply press a button on the neckstrap or wristband, which sends a signal to a unit by the phone, which in turn sends out a signal to a call centre which can dispatch a carer or relative to deal with the problem.

Such call centres are continuously manned by a number of staff.

However, using the above described system, after activation of the alarm, the user has no way of knowing if their call has been received, and no reassurance that their call has been processed and that assistance is on the way.

Some systems incorporate a loudspeaker phone that allows two-way communication, but this system relies on the elderly person being close to the phone.

A system, called the Talkback system, has recently been introduced by Tunstall Telecom Limited. This has a portable trigger of about 15 cm in length which allows two-way communication within 100 metres of a unit by the telephone.

The Talkback device is too large to be worn around the neck or the wrist, and the manufacturers also recommend that the batteries be charged daily.

Therefore, there is a need for an alarm system that enables two-way communication with a warden or other helper and that is small enough to be easily portable and that has a battery life long enough to ensure the system does not need recharged at inconveniently frequent intervals.

According to a first aspect of the present invention there is provided a personal alarm system comprising trigger means enabled to send command and communication signals to a telephony interface unit, receive communication signals from the telephony interface unit, send prompt signals and communication signals to a user, and receive command and communication signals from the user, such that a two-way communication link can be established between the user and a remote aid source.

Preferably, the trigger means further comprises speech recognition software that is capable of recognising command signals sent vocally from the user and of enabling the trigger means to output the appropriate command signals to the telephony interface unit, depending on the nature of the command signals from the user. Preferably, the command signals sent from the trigger means to the telephony interface unit enable the telephony interface unit to select an appropriate node on a standard telephone network to contact .

Preferably, the speech recognition software is trainable to recognise a selection of key words which correspond to the command signals sent from the trigger means to the telephony interface unit .

Preferably the speech recognition software comprises a first component for recognition of the selection of key words, and a second component for recognition of a wider selection of speech strings.

Preferably, the first component is a low power component that can be continuously active.

Preferably, the second component is activated by utterance of a specific key word.

Preferably, the second component is trainable to function as a telephone directory.

Preferably, the trigger means further comprises a vibration sensor for sensing the vibration of the user's throat, and a command signal is only sent from the trigger unit to the telephony interface unit upon both the recognition of a keyword command and the confirmation of the existence of throat vibration. Optionally, the vibration sensor can sense the vibration of the user's chest.

Preferably, the trigger means comprises an inclinometer such that a command signal can be generated if the user falls over.

Preferably, the 'inclinometer can act in conjunction with an accelerometer to determine when the user has fallen.

Preferably, the trigger means comprises a speaker to transmit the prompt signals and communication signals from the trigger means to the user as sound waves.

Preferably, the prompt signals serve as a command confirmation means.

Preferably, the trigger means comprises speech synthesis software for generating the prompt signals which are sent from the trigger means to the user.

Optionally, the prompt signals are generated by the playing of a pre-recorded message.

Optionally, the trigger means comprises transmitter means to transmit the prompt and communication signals from the trigger means to an induction loop of a hearing aid worn by the user. Preferably, the prompt and communication signals are sent to the hearing aid as an electromagnetic field for conversion to sound by the induction loop.

Optionally, the trigger means comprises a radio transmitter to transmit prompt and communication signals as radio-frequency electromagnetic waves, and the hearing aid comprises a radio receiver to receive the prompt and communication signals.

Preferably, the hearing aid is provided with an automatic switching means which switches from a first position in which the induction coil is engaged to a second position in which the induction coil is disengaged and which is latched on to the first position when the prompt and communication signals are received from the trigger means.

Preferably, the induction coil stays in its first position when the prompt signal and communication signals reach the hearing aid.

Preferably, the trigger means comprises transceiver means for receiving the communication signals from the user and sending the communication signals to the telephony interface unit.

Preferably, the transceiver means sends the communication signals to and receives the communication signals from the telephony interface unit as electromagnetic waves. Preferably, the trigger means is provided as a unitary article.

Optionally, the components of the trigger means may be provided in a distributed fashion.

Preferably, the components of the trigger means are suitable for distribution within pockets of a belt to be worn by the user.

Preferably, the belt is made from an electrically conductive material .

Optionally, the components of the trigger means are distributed within pockets in a vest to be worn by the user.

Preferably, the vest is made from an electrically conductive material.

Preferably, the remote aid source is an operator at a call centre, who can arrange for help to be sent to the user if the user is in distress.

Optionally, the remote aid source can be any person or establishment that the user wishes to contact.

According to a second aspect of the present invention there is provided a personal alarm system comprising; a telephony interface unit comprising means to initiate, maintain and end a communication session over a standard telephone network; and trigger means enabled to send command and communication signals to the telephony interface unit, receive communication signals from the telephony interface unit, send prompt signals and communication signals to a user, and receive command and communication signals from the user, such that a two-way communication link can be established between the user and a remote aid source.

Preferably, the telephony interface unit is engageable with a telephone to instruct the telephone to initiate, maintain and end a communication session over a standard telephone network.

According to a third aspect of the present invention, there is provided a method of providing a personal alarm system wherein; a user sends command and communication signals to a trigger means and receives prompt signals and communication signals from the trigger means; and the trigger means sends command and communication signals to a telephony interface unit and receives communication signals from the telephony interface unit, such that a two-way communication link is established between the user and a remote aid source. Preferably, the telephony interface unit sends communication signals to and receives communication signals from the remote aid source over a standard telephone network.

Preferably, the telephony interface unit engages with a telephone and instructs the telephone to initiate, maintain or end a communication session over a standard telephone network.

Preferably, the trigger means comprises speech recognition software which is trained to recognise a selection of key words.

Preferably, the command signals sent from the user to the trigger means comprise an utterance of at least one of the key words.

Optionally, the trigger means is provided with a panic button which can be pressed for a pre- determined period of time to send a command signal corresponding to a request for aid to the telephony interface unit.

Preferably, when the trigger means receives a command signal from the user that corresponds to a request for aid, the trigger means transmits a prompt signal to the user to invite him to confirm his request for aid.

Preferably, the prompt signal is generated by speech synthesis software. Optionally, the prompt signal is provided by the playback of a pre-recorded message.

Preferably, the user confirms his request for aid by repeating the original command signal.

Optionally, the user confirms his request for aid by sending a distinct affirmative command signal.

Preferably, the user can respond to the prompt signal by sending a command signal to cancel his request for aid.

Preferably, once the command signal corresponding to a request for aid has been confirmed, the trigger means sends a command signal to the telephony interface unit, to initiate a telephone call to a remote aid source.

Preferably, if the user does not respond to the prompt signal within a pre-set time, the trigger means proceeds to send a command signal to the telephony interface unit to initiate a telephone call to a remote aid source.

Preferably, the trigger means selects an appropriate command signal to send to the telephony interface unit depending on the specific key word that is uttered. Preferably, the command signals sent from the trigger means to the telephony interface unit are sent as electromagnetic waves.

According to a second embodiment of the present invention, there is provided a call centre which comprises means to receive an incoming call, means to identify the purpose of the call, and means to route the call to an appropriate remote helper.

Preferably, the call centre is unmanned, and interactive voice technology is used to manage the caller's query and transfer the call to the remote helper.

Optionally, the call centre is manned by agents who speak to a caller before transferring their call to the remote helper.

Preferably, the incoming call is passed through a telephone switch before being passed on to a switch server which acts as a bridge between the telephone switch, a core server and client applications accessible by the agent.

Preferably, the core server contains caller-relevant data.

Specific embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which; Fig. 1 is a schematic diagram of a first aspect of the present invention;

Fig. 2 is a schematic diagram of a further implementation of the aspect shown in Fig. 1;

Fig. 3 is a diagram illustrating features of a trigger unit provided in the invention; and

Fig. 4 illustrates a second embodiment of the present invention, in which a call centre is provided.

In use, the system establishes a two-way communication link between the user 10 and a remote helper at a call centre 70. This two-way communication is illustrated in Fig. 1. The user 10 either carries or wears a personal alarm trigger unit 30, which includes a speaker to transmit prompt signals 38 and communication signals 39 to the user 10. A microphone and transceiver are included within the trigger unit 30 for picking up the user's voice 40 and transmitting it to a telephone interface unit 50. The user's voice 40 acts as a signal transmitting commands or general communication.

The trigger unit 30 also sends command and communication signals 36 to the telephone interface unit 50, and receives communication signals 58 from the telephone interface unit 50. In the embodiment illustrated, the signals 36, 58 are transmitted using DECT at a frequency of 1.8 GHz, although different frequency bands, such as 863-865 MHz or 2.4 GHz bands could be used. Furthermore, alternative communications standards could be used, for example, Bluetooth, HomeRF, IEEE 802.11b, GPRS or Hiperlan. The communication standard used could also be a custom communication standard specifically designed for use with a personal alarm system according to the present invention.

The telephone interface unit 50 co-operates with a telephone 60, sending communication signals 56 and receiving communication signals 68 so that a call comprising communication signals 66 and 78 is placed over a standard telephone network to a call centre 70.

Thus, when the system is in full operation, a two- way communication link is in place, the voice of the remote helper being heard by the user via the communication signals 78, 68, 58, and 39, and the voice of the user is heard by the remote helper via the communication signals 40, 36, 56, and 66.

This two-way link enables the helper in the call centre to provide reassurance that help is on its way, and also to ask the user to describe the exact nature of their dilemma, so that appropriate assistance can be delivered.

When a user 10 activates the alarm, the trigger unit 30 sends prompt signal 38, to prompt the user to confirm that the request for help is a genuine request for help.

This is desirable because with present systems, a significant percentage of call-outs are false alarms, for example, the button on current systems could be pressed accidentally, or the user could mis-use the system by calling an emergency operator when it would be more appropriate to be put through directly to a grocery store or suchlike.

Thus, the step of confirming an alarm activation significantly reduces the number of false alarms, which in turn will reduce the running costs of call centres and manned warden systems.

This prompting is achieved by the incorporation of speech recognition and speech synthesis software in the trigger unit 30.

The trigger 30 is activated by the utterance of a key word, which is picked up by a microphone in the trigger 30 and recognised by the speech recognition software, which has been trained to recognise selected key words. In this embodiment, the key word that activates the trigger is "Help!"

Upon recognition of the key word, the speaker transmits a prompt signal 38 to the user 10. The prompt signal 38 is generated by the speech synthesis software, and comprises a phrase prompting the user 10 to confirm whether the request for help is a genuine emergency or not. The user 10 responds with a second key word, which again is picked up by the microphone in the trigger 30 and recognised by the speech recognition software. In this preferred embodiment, the speech recognition software is trained to recognise either of the second key words "Yes" and "No."

If the user 10 confirms they need assistance by saying "Yes" in reply to the prompt signal 38, the trigger 30 then transmits a command signal 36 to the telephone interface unit 50 to initiate the two-way communication link.

If the alarm was activated accidentally, or the request is a non-urgent one, the user 10 responds by saying "No" in reply to the prompt signal 38 and a command signal 36 is not transmitted to the telephone interface unit 50.

As a back-up, if the user 10 utters the key word to request help, and no response is made in response to the prompt signal 38, then after a predetermined time that may, for example, be one minute, the trigger 30 will proceed to initiate the two-way communication link.

This is done to guarantee that the user 10 can still get help if he becomes incapacitated after initial activation of the alarm. The trigger may also be provided with a vibration sensor that picks up vibrations in a user's throat or chest. When a command signal corresponding to a request for help is received by the trigger unit 30, the output from the vibration sensor is checked to ensure that the user is actually speaking. If not, the request for help is cancelled. This ensures that a false alarm is not generated by, for example, a noise on the television, or an utterance made by someone else in conversation.

Fig. 3 shows a selection of the components that make up the trigger unit 30.

The microphone/transceiver is linked to the telephone or to the telephone interface unit. The baseband chip contains protocols for connecting to the PSTN, and can also be equipped with protocols for connecting to other telecommunication network components.

In the most preferred implementation, separate simple and complex speech recognition components, and speech synthesis components are all implemented on the same silicon chip, which enables the trigger unit 30 to be relatively small in size, and suitable to be worn as a pendant or other piece of jewellery.

The simple key word speech recognition component is trained to recognise a selection of key words. In this embodiment, the key words include "Help!", "Yes" and "No". The complex speech recognition component is used when, for example, the system is used as a mobile telephone and the user can select different telephone numbers to call via a voice command. The simple speech recognition component is also trained to recognise a command that activates the complex speech recognition component. For example, the simple speech recognition component could be further programmed to recognise the word "Phone" , upon which the complex speech recognition component, which has been trained to recognise a wide range of names, is activated, and a further command word can be spoken to dial up the number of a specific person, shop, or any other number the user wants to store.

The complex speech recognition component could also be trained to recognise individual numbers, such that the user can merely dictate a number to be dialled. Therefore, the personal alarm system can also be used as a fully functional mobile telephone. In this regard, the system can also be provided with a list of telephone numbers which the user can cycle through by subsequent presses of a button on the trigger unit, the speech synthesis component speaking the identifying name associated with the numbers as the user scrolls through them, to help the user keep track of where he is on the list.

The simple speech recognition component consumes relatively little power, and so can be left switched "on" all the time. As described above, the higher- powered complex speech recognition component is only activated when needed. This makes the system more energy efficient, and results in longer battery life of the trigger unit 30.

In an alternative implementation, there is a single speech recognition component, which operates in conjunction with a low powered front end. The low powered front end comprises a voice operated switch which ignores continuous speech, but switches on the speech recognition component upon hearing an isolated word. The speech recognition component can then decide whether the isolated word is one of the keywords.

In this way, power efficiency of the system is improved, with the relatively low powered voice operated switch being left permanently switched on, and the relatively high powered speech recognition component only being used when needed.

It should also be recognised that any suitable practical implementation of the above concepts is included in the scope of the present invention, for example, the simple and complex speech recognition software components could each be implemented on separate chips, or speech recognition could be implemented on one chip with speech synthesis being implemented on another.

The manufacturer of the invention can also be flexible in his chip design. For example, he could choose whether to design both the complex and simple speech recognition chips, or he could design his own simple speech recognition chip and use a currently available chip to serve as the complex recognition chip. This embodiment is also able to be implemented for users who are hard of hearing and wear hearing aids, as is shown in Fig. 2.

In this case, the speaker in the trigger 30 is replaced by a transmitter for transmitting communication signals 80 as electromagnetic waves that are converted to sound by the induction coil in a hearing aid 20. The transmitter suitably takes the form of a loop of wire, and transmits at a suitable frequency so that the signal 80 generated by the transmitter loop can be easily converted to sound by the induction loop of the hearing aid 20.

Alternatively, the trigger unit 30 can be provided with a radio transmitter and the hearing aid 20 can be provided with a radio receiver for the transmittal of the abovementioned signals.

The communication signals 80 are converted into sound only when the induction coil of the hearing aid 20 is active, that is, when the hearing aid 20 is switched to its "T" position, so that the user 10 obtains signals from an induction coil contained in the hearing aid 20.

Thus, the present invention also provides for a hearing aid 20 that monitors the "T" position. However, when the hearing aid 20 receives communication signals 80 from the trigger unit 30, it switches to a constant "T" position such that the user can hear the message to be transmitted. The invention also provides for the provision of a light or a buzzer in the trigger unit 30 which indicates when the trigger unit 30 has been activated. This is useful when the user 10 is wearing a standard hearing aid 20 and has not switched his hearing aid 20 to the "T" position.

Of course, if a hearing aid wearer so chooses, they can use the speaker version rather than the hearing aid version.

As a further guarantee that help can be obtained, the invention can function without the use of speech recognition software. This is desirable because there may be cases where speech recognition may be inappropriate, for example where there is a lot of background noise, or where the user 10 is incapacitated in such a way as to not be able to speak.

Instead of using speech recognition software to recognise when the alarm has been activated, a button is used to activate the trigger unit 30.

When the button is pressed, the speech synthesis software in the trigger unit 30 generates a prompt signal 38 inviting the user 10 to confirm or cancel his request for help. The user 10 then replies with further pressing of the button. In this embodiment, the user 10 presses the button either once to confirm his request, or twice to cancel his request. It will be appreciated that the user 10 can also cancel or confirm his request by saying a command that is recognised by the speech recognition software.

If no further button presses or spoken responses are detected after a set time, for example one minute, the trigger 30 proceeds to send a command signal corresponding to a request for help.

Also, a call could be automatically put through to the remote helper if the button is held down for a predetermined length of time, which could for example be ten seconds .

After initial activation of the trigger 30, the user 10 can choose to call a particular telephone number from a list of available numbers. He can use a voice command to dial these numbers, with the speech recognition software in the trigger unit 30 being trained to recognise the names or numbers of the people the user 10 wishes to call.

Thus, the present invention can effectively be used as a mobile telephone.

The present invention could also comprise a fall detector comprising an inclinometer, which could be set up to generate an alarm signal under specific conditions. These conditions should be such that shaking or other movements are not mistaken for a fall. In addition, a user may need to wear the alarm when carrying out an activity which involves some leaning over, for example gardening. It is important that false alarms are not generated here, as these would annoy the user and make them feel like removing the alarm when they are carrying out that particular activity.

A digital inclinometer will monitor the orientation of the user to assess whether they are in an upright or fallen position. Such an inclinometer could be improved by incorporating an accelerometer, and an emergency could be adjudged to have arisen when the digital inclinometer indicates the user is in a fallen position, and the accelerometer indicates that they have moved at a rate outside of a pre- defined safe limit.

Alternatively, an analogue implementation of the inclinometer could be provided. This would measure the actual angle of inclination of the user, and could provide an alarm signal based on either or both of whether a user has been in a "fallen" position for longer than a pre-set amount of time, or whether the angular rate of change exceeds a pre- defined safe limit.

The criteria that either the digital or analogue inclinometers use to make the measurements described above could be implemented by any suitable algorithm.

Other features that can be incorporated within the present invention include providing an activity monitor, to detect body movement to give a monitoring tool to measure the activity of a user; a breathing and/or heart rate monitor, and other mechanisms to monitor habits and locations of the user 10, to provide information or to generate an alarm signal if the user 10 goes outside a specified area.

The invention has been described thusfar in general terms with respect to the location of the various components. However, the trigger unit 30 could be provided in a variety of forms. One option is for the trigger unit 30 to be provided as a unitary article, which can be easily carried or worn round the user's neck.

The components of the trigger unit 30 may also be distributed in various pockets or compartments on a belt, or in a vest to be worn by the user. A suitable clothing implementation could be found that would allow the alarm to be worn twenty-four hours a day, and the components could be easily removable from pockets in a vest so that the vest can be easily washed.

Also, a "smart clothing" implementation can be carried out, wherein the belt or the vest is formed from an electrically conductive material, for example silk organza. Thus, signals can travel between the components of the present invention by means of the smart clothing.

The speaker, microphone and vibration sensor could also be located separately from the rest of the components so that they are located close to the user's head, to improve performance of the system.

The invention can be marketed as a modular system, with consumers being able to select which version they would like to buy, and which features they would like to be incorporated therein.

Fig. 4 shows the operation of a call centre management system in accordance with the present invention.

An incoming call 100 is received by a telephone switch 110, and passed to a switch server 120. The switch server 120 then acts as a bridge between a core server 130, client applications 140, and the telephone switch 110.

The telephony link by which the telephone switch 110 receives the incoming call 100 is an asymmetric link, with the downlink transmitting DTMF (Dual tone multi frequency) codes (typically at a rate of 5-10 digits per second) and speech from the user of the personal alarm system, and the uplink transmitting FSK (frequency shift keying) modem data (typically at a rate of 2400 baud) and speech to the user of the personal alarm system. This asymmetric link is suitable because there is no requirement for large volume data traffic on the downlink.

An arriving call 100 is brokered by the telephone switch 110 to identify the reason for the call, and CLI (calling line identification) can be used to identify the caller, enabling relevant supporting data to be gathered from the configuration database on the core server 130.

The call 100 is directed to the agent's headset or telephone handset, and the client applications 140 are run on the agent's computer.

The client applications 140 include an application which reads and displays customer-specific data from the configuration database in the core server 130. This data can be the customer's address and contact details, or those of their family, friends, doctor, or other appropriate contacts, and can be gathered either automatically from identification of the caller's telephone number, or upon enquiry as to the identity of the caller.

The client applications 140 also include a configuration manager to manage and update the data on the configuration database, monitoring programmes which gather and sort statistics for auditing and accounting purposes, and a legacy bridge to provide the exchange of real-time data. When an agent is available, the core server 130 presents the call 100 to the agent and also transmits a notification to the client application 140 so that the agent can access the customer related data from their workstation.

The call centre can be manned, with agents' workstations being connected to the core server by a LAN (local area network) , or by a bridging medium such as ISDN (integrated services digital network) via a router, so that the agents can be situated either at or remote from the call centre.

When a customer is put through to an agent, the agent can communicate with the customer and arrange to send help, which he can do by contacting a number which he obtains from the configuration database. The customer can stay on the line while the agent makes this call, and a three-way communication link can be established if desired.

However, the call centre can also be unmanned, in which case interactive voice technology can be used to direct a call to a contact help number obtained from the configuration database. In this case, the user will be prompted to enter a simple DTMF code when they make successful contact, thus ensuring that connection with a modem, fax machine or answering machine is not interpreted by the system as a successful connection. It is possible to offer a customer a choice of whether they want a service which provides a manned or unmanned call centre. A composite service can also be offered, which offers an unmanned service with one backup agent on hand should nobody on the customer's contact list be available.

The core server 130 interprets an incoming call 100 and decides whether the call 100 is to be passed directly to an agent or if it is to be treated as an unmanned call. It then queues the call using ACD (automated call distribution) technology provided by the telephone switch 110, putting the customer on hold if necessary.

The core server 130 also logs agent operations for the purposes of auditing the system and measuring performance.

The provision of an unmanned call centre can appreciably reduce the running costs of warden-style personal alarm systems.

While the above is a description of preferred embodiments of the present invention, it will be appreciated that various modifications may be made without departing from the scope of the invention.

As described above, in one implementation of the invention, a speaker is incorporated in the trigger unit, and in a second implementation of the invention, for use with hearing aids, the speaker is described as being replaced by a transmitter. It is to be understood that in the hearing aid implementation of the present invention, both a transmitter and a speaker could be provided, so that either the user could choose which implementation he prefers, or the invention as sold could be used by a variety of users, who may or may not be hard of hearing.

In particular, the trigger unit can be worn as a neck loop, wrist watch or any other piece of jewellery, the key words that the speech recognition software is trained to recognise could be different words, or the same words in different languages, and the default destination of an initiated two-way communication link may be somewhere other than a call centre.

The principles of the invention may also be applied to home gadget control or physiological monitoring. They can also be applied so that the system acts as a hands-free mobile phone kit. The modular nature of the system ensures its flexibility for a wide range of applications.

Claims

1. A personal alarm system comprising trigger means enabled to send command and communication signals to a telephony interface unit, receive communication signals from the telephony interface unit, send prompt signals and communication signals to a user, and receive command and communication signals from the user, such that a two-way communication link can be established between the user and a remote aid source.

2. The personal alarm system of claim 1, wherein the trigger means further comprises speech recognition software that is capable of recognising command signals sent vocally from the user and of enabling the trigger means to output the appropriate command signals to the telephony interface unit, depending on the nature of the command signals from the user.

3. The personal alarm system of any preceding claim, wherein the command signals sent from the trigger means to the telephony interface unit enable the telephony interface unit to select an appropriate node on a standard telephone network to contact.

4. The personal alarm system of claim 2 or claim 3, wherein the speech recognition software is trainable to recognise a selection of key words which correspond to the command signals sent from the trigger means to the telephony interface unit .

5. The personal alarm system of claim 4, wherein the speech recognition software comprises a first component for recognition of the selection of key words, and a second component for recognition of a wider selection of speech strings.

6. The personal alarm system of claim 5, wherein the first component is a low power component that can be continuously active.

7. The personal alarm system of claim 5 or claim 6, wherein the second component is activated by utterance of a specific key word.

8. The personal alarm system of any of claims 5-7, wherein the second component is trainable to function as a telephone directory.

9. The personal alarm system of any preceding claim, wherein the trigger means further comprises a vibration sensor for sensing the vibration of the user's throat, and a command signal is only sent from the trigger unit to the telephony interface unit upon both the recognition of a keyword command and the confirmation of the existence of throat vibration.

10. The personal alarm system of any of claims 1-8, wherein the trigger means further comprises a vibration sensor for sensing the vibration of the user's chest, and a command signal is only sent from the trigger unit to the telephony interface unit upon both the recognition of a keyword command and the confirmation of the existence of chest vibration..

11. The personal alarm system of any preceding claim, wherein the trigger means comprises an inclinometer such that a command signal can be generated if the user falls over.

12. The personal alarm system of claim 11, wherein the inclinometer can act in conjunction with an accelerometer to determine when a user has fallen.

13. The personal alarm system of any preceding claim, wherein the trigger means comprises a speaker to transmit the prompt signals and communication signals from the trigger means to the user as sound waves.

14. The personal alarm system of any preceding claim, wherein the prompt signals serve as a command confirmation means.

15. The personal alarm system of any preceding claim, wherein the trigger means comprises speech synthesis software for generating the prompt signals which are sent from the trigger means to the user.

16. The personal alarm system of any of claims 1- 14, wherein the prompt signals are generated by the playing of a pre-recorded message.

17. The personal alarm system of any of claims 1- 12, wherein the trigger means comprises transmitter means to transmit the prompt and communication signals from the trigger means to an induction loop of a hearing aid worn by the user.

18. The personal alarm system of claim 17, wherein the prompt and communication signals are sent to the hearing aid as an electromagnetic field for conversion to sound by the induction loop.

19. The personal alarm system of claim 17, wherein the trigger means comprises a radio transmitter to transmit prompt and communication signals as radio- frequency electromagnetic waves, and the hearing aid comprises a radio receiver to receive the prompt and communication signals.

20. The personal alarm system of any of claims 17- 19, wherein the hearing aid is provided with an automatic switching means which switches from a first position in which the induction coil is engaged to a second position in which the induction coil is disengaged and which is latched on to the first position when the prompt and communication signals are received from the trigger means.

21. The personal alarm system of claim 20, wherein the induction coil stays in its first position when the prompt signal and communication signals reach the hearing aid.

22. The personal alarm system of any preceding claim, wherein the trigger means comprises transceiver means for receiving the communication signals from the user and sending the communication signals to the telephony interface unit.

23. The personal alarm system of claim 22, wherein the transceiver means sends the communication signals to and receives the communication signals from the telephony interface unit as electromagnetic waves.

24. The personal alarm system of any preceding claim, wherein the trigger means is provided as a unitary article.

25. The personal alarm system of any of claims 1- 23, wherein the components of the trigger means may be provided in a distributed fashion.

26. The personal alarm system of claim 25, wherein the components of the trigger means are suitable for distribution within pockets of a belt to be worn by the user.

27. The personal alarm system of claim 26, wherein the belt is made from an electrically conductive material.

28. The personal alarm system of claim 25, wherein the components of the trigger means are distributed within pockets in a vest to be worn by the user.

29. The personal alarm system of claim 28, wherein the vest is made from an electrically conductive material.

30. The personal alarm system of any preceding claim, wherein the remote aid source is an operator at a call centre, who can arrange for help to be sent to the user if the user is in distress.

31. The personal alarm system of any of claims 1- 29, wherein the remote aid source can be any person or establishment that the user wishes to contact.

32. A personal alarm system comprising; a telephony interface unit comprising means to initiate, maintain and end a communication session over a standard telephone network; and trigger means enabled to send command and communication signals to the telephony interface unit, receive communication signals from the telephony interface unit, send prompt signals and communication signals to a user, and receive command and communication signals from the user, such that a two-way communication link can be established between the user and a remote aid source .

33. The personal alarm system of claim 32, wherein the telephony interface unit is engageable with a telephone to instruct the telephone to initiate, maintain and end a communication session over a standard telephone network.

34. A method of providing a personal alarm system wherein; a user sends command and communication signals to a trigger means and receives prompt signals and communication signals from the trigger means; and the trigger means sends command and communication signals to a telephony interface unit and receives communication signals from the telephony interface unit, such that a two-way communication link is established between the user and a remote aid source.

35. The method of claim 34, wherein the telephony interface unit sends communication signals to and receives communication signals from the remote aid source over a standard telephone network.

36. The method of claim 34 or claim 35, wherein the telephony interface unit engages with a telephone and instructs the telephone to initiate, maintain or end a communication session over a standard telephone network.

37. The method of any of claims 34-36, wherein the trigger means comprises speech recognition software which is trained to recognise a selection of key words .

38. The method of claim 37, wherein the command signals sent from the user to the trigger means comprise an utterance of at least one of the key words .

39. The method of any of claims 34-38, wherein the trigger means is provided with a panic button which can be pressed for a pre-determined period of time to send a command signal corresponding to a request for aid to the telephony interface unit.

40. The method of any of claims 34-39, wherein, when the trigger means receives a command signal from the user that corresponds to a request for aid, the trigger means transmits a prompt signal to the user to invite him to confirm his request for aid.

41. The method of claim 40, wherein the prompt signal is generated by speech synthesis software.

42. The method of claim 40, wherein the prompt signal is provided by the playback of a pre-recorded message.

43. The method of any of claims 40-42, wherein the user confirms his request for aid by repeating the original command signal.

44. The method of claim 43, wherein the user confirms his request for aid by sending a distinct affirmative command signal.

45. The method of any of claims 40-44, wherein the user can respond to the prompt signal by sending a command signal to cancel his request for aid.

46. The method of any of claims 40-45, wherein, once the command signal corresponding to a request for aid has been confirmed, the trigger means sends a command signal to the telephony interface unit, to initiate a telephone call to a remote aid source.

47. The method of any of claims 40-46, wherein, if the user does not respond to the prompt signal within a pre-set time, the trigger means proceeds to send a command signal to the telephony interface unit to initiate a telephone call to a remote aid source.

48. The method of any of claims 38-47, wherein the trigger means selects an appropriate command signal to send to the telephony interface unit depending on the specific key word that is uttered.

49. The method of any of claims 34-48, wherein the command signals sent from the trigger means to the telephony interface unit are sent as electromagnetic waves.

50. A call centre which comprises means to receive an incoming call, means to identify the purpose of the call, and means to route the call to an appropriate remote helper.

51. The call centre of claim 50, wherein interactive voice technology is used to manage the caller's query and transfer the call to the remote helper, enabling the call centre to be unmanned.

52. The call centre of claim 50, being manned by agents who speak to a caller before transferring their call to the remote helper.

53. The call centre of any of claims 50-52, wherein the incoming call is passed through a telephone switch before being passed on to a switch server which acts as a bridge between the telephone switch, a core server and client applications accessible by the agent.

54. The call centre of claim 53, wherein the core server contains caller-relevant data.