GB2206017A - Emergency call system - Google Patents

Abstract

An emergency speech communication system for use with a plurality of remote call stations (2). At each call station there is a call unit (1) having a call raising switch and sound transducer means. Transmission means (6) interconnect the call units with a master unit (5) for conveying data, control signals and audio signals between the master unit and each call unit. A personal radio transmitter unit (9) is associated with each call unit, and is operable to issue a call radio signal which is distinctive of its own call unit. A central radio receiver (41) is arranged to receive the call radio signal and is connected to a control unit (7), which responds to a received call radio signal to raise a call on the system in the same way as if the call raising switch of the call unit had been operated. A self-test arrangement provided in the control unit includes a timer operative to initiate a warning signal after a predetermined period unless re-set to zero within that period. A fixed radio transmitter (43) is triggered by the control unit at regular intervals to issue a test radio signal distinctive of the fixed radio transmitter. The control unit (7) is responsive to a received test radio signal to cause the timer to re-set to zero, and means are provided in the control unit responsive to the warning signal from the timer for initiating a warning call on the system indicative of a failure of the central radio receiver, in the event of the predetermined period expiring without the timer having been re-set to zero. <IMAGE>

Description

EMERGENCY CALL SYSTEM This invention relates to a speech emergency call system.

Emergency call systems for elderly or infirm people have become widespread, perticularly in sheltered sousing schemes. Such systems permit an emergency call, from equipment in a resident's dwelling, to be transmitted to the office of a warden or guardian by way of a private telecommunication network.

Early examples of such systems comprised a central control cabinet, located typically in the warden's office or dwelling, connected by a radial pattern of cables to a wall-mounted alarm panel in each resident's dwelling. The alarm panel usually featured a switch, of the push-button or pull-cord type, operated by the resident to raise a call, and an indicator light whose purpose was, by lighting-up when a call was raised, to reassure the resident that the equipment was functioning correctly in the event of the warden not answering the call immediately.

More advanced systems incorporated two-way speech communication between the resident and the warden, the resident's wall-mounted alarm panel incorporating loudspeaker and microphone equipment for this purpose.

The warden's control cabinet generally incorporated an indicator light and a switch for each resident protected by the system, the light serving to identify the calling resident to the warden, and the switch to connect the warden's speech equipment to the appropriate resident's alarm unit. In addition, the central control cabinet featured a two-position talk/listen switch, whereby the warden controlled the speech direction during calls.

In recent times, emergency call systems of the type described here have benefitted from technological advance in a number of ways: firstly the pattern of radial cabling whereby the residents' alarm units were connected to the central control unit has been superseded by parallel cabling whereby all residents' alarm units are identically connected to the conductors of a single cable, with system control functions executed by digital signalling between the respective items of equipment.

Secondly, body-worn radio transmitter devices are available whereby the resident may raise an emergency call from any location in his/her dwelling, without the need for switches to be deployed in each room and wired to the alarm panel.

Such devices have a cord enabling the device to be worn around the neck, and have a push button which is pressed in order to initiate an emergency call.

Radio trigger devices of this nature usually communicate with a radio receiver, located at a central point in the sheltered housing scheme. The receiver, upon receipt of a signal from a residents body-worn radio transmitter, feeds the signal, which contains encoded data identifying the resident who raised the call, to the cable network. The central control unit then interprets this signal as an indication that a particular resident has raised a call, and makes the warden aware of this by a combination of audible and visible signals, typically by emitting a "bleeping" tone and displaying the number of the resident's dwelling, in exactly the same manner as if the call had been raised by the resident operating the switch on his/her alarm panel.

It will be apparent that if any fault should develop at the central receiver, this would have the result that there would be response to an attempt at initiating an emergency call by pressing the push button of the personal radio transmitter. The present invention has therefore been developed primarily, though not exclusively, with a view to providing an improved speech emergency call system, incorporating one or more body-worn radio transmitters as referred to above, in which there is an automatic indication of a potential situation in which an emergency call initiated on the radio transmitter would go unnoticed and therefore not be responded to.

According to the invention there is provided an emergency speech communIcation system for use with a plurality of remote call stations, and which comprises: a master unit having data display means, data entry means and sound transducer means associated therewith; a plurality of call units each for location at a respective call station and having a call raising switch and sound transducer means; transmission means for interconnecting the master unit and the call units for conveying data, control signals and audio signals between the master unit and each call unit; a control unit having electronic control circuitry for controlling the operation of the system; at least one personal radio transmitter unit associated with a respective one of said call units, and operable to issue a call radio signal which is distinctive of said one call unit;; a central radio receiver arranged to receive the call radio signal and connected to the control unit, the control unit being responsive to a received call radio signal to raise a call on the system in the same way as if the call raising switch of said one call unit had been operated; a self-test arrangement provided in the control unit and including a timer operative to initiate a warning signal after a predetermined period unless re-set to zero within that period; a fixed radio transmitter unit linked to the control unit such that the control unit, under the control of the timer, triggers the transmitter unit at regular intervals to issue a test radio signal distinctive of the fixed radio transmitter unit and to be received by the central receiver; the control unit being responsive to a received test radio signal to cause the control unit to re-set the timer to zero; and means provided in the control unit and responsive to the warning signal from the timer for initiating a warning call on the system indicative of a failure of the central radio receiver, in the event of the predetermined period expiring without the timer having been re-set to zero.

The control unit therefore continuously monitors the ability of the central receiver to respond to a genuine emergency call from one of the personal radio transmitter units, in that the fixed radio transmitter unit, linked to the control unit, is triggered into operation at regular intervals, under the control of the timer, so as to issue its own test radio signal to the central receiver which, when properly received, inhibits the control unit from raising a warning call on the system. When not properly received, however, a warning call is raised to give an indication of the system failure.

Preferably a plurality of personal radio transmitter units are provided, each associated with a respective one of the call units.

Suitable electronic circuitry will be provided in the control unit and the central receiver to permit the system to operate in the required manner, both during normal operation of the system between master and call units, and via the personal radio transmitter units; and also during the continuous self-test facility provided by the control unit, the fixed radio transmitter unit and the central receiver.

Conveniently, the fixed radio transmitter unit is of a generally similar construction to that of the personal radio transmitter units, though programmed to have its own distinctive test radio signal which can be recognised by the control unit.

An embodiment of emergency speech communication system according to the invention will now be described in detail, by way of example onlyr with reference to 1(;e c'cmDnyin drawings, in which: Figure 1 is a schematic drawing of an emergency speech communication system incorporating the invention; and Figure 2 is a schematic diagram of electronic components incorporated in the communication system.

Referring now to Figures 1 and 2 of the drawings, these show schematically a speech emergency call system which comprises a number of call'units 1 each arranged at a respective remote call station, which takes the form of a dwelling 2 for a resident 8 of a sheltered housing scheme.

A central station 3 has a further call unit 4, the station 3 comprising the office and/or dwelling of a warden or guardian. The call unit 4 may be generally similar to each call unit 1, but a portable master unit 5 is normally plugged into the unit 4 for use by the warden in order to receive, and to send-out calls. The master unit is also capable of being plugged into an electrical connector 3a of any call unit, when the warden is in a resident's dwelling.

A central control unit 7 is provided, which may be located at the central station 3, and which incorporates electronic circuitry to control the operation of the system. All of the components of the system are connected in common by transmission means for conveying data, control signals and audio signals between the master unit 5, the control unit 7 and each call unit, the transmission means typically being a 10-core cable 6.

Each call unit is a small wall-mounted alarm panel incorporating a microphone 16 and loudspeaker 17 with associated amplification and switching circuitry, a momentary action call-raising switch 10, e.g. a pushbutton on the panel and a microprocessor 12 for controlling operation of the call unit. The control unit 7 provides an overall system control function which will be described in more detail in the description of system operation which follows.

The master unit 5 incorporates a display element 23 (see Figure 2), typically a liquid crystal display on which the identity of calling call units is displayed in the form of numeric codes, and a keypad 22 with numeric keys and keys dedicated to specific call handling functions.

Control of the master unit is effected by a microprocessor 24, and the unit is connected to the system cable by way of the connector 3a of any call unit.

To raise an emergency call, the resident 8 presses the switch 10 his the call unit 1. The effect of this is to place a signal on an input line of microprocessor 12, causing the microprocessor to read a transmitted numerical identification code for the call unit from a memory device 13 and transmit this to the control unit 7 in the form of digital signalling on the 10-core cable 6. The transmitted numerical identification code is stored in a further memory device 20 in the control unit 7. The memory of the control unit is scanned under control of a microprocessor 21 at fixed intervals, e.g. every three seconds, and its contents, i.e. one or more call unit identification codes, transmitted on the system cable 6 in the form of data packets prefixed with an address exclusive to the master unit 5.The codes are received by the master unit 5 and displayed in cyclic sequence in the LCD display 23.

Receipt of data from the control unit also causes the master unit to emit a tone, drawing the arrival of a call to the attention of the warden or guardian. The warden may then initiate speech contact with any calling resident by pressing a SELECT key on the master unit keypad 22 whilst the identification code of that resident's call unit is displayed.

The effect of this is to transmit an enable signal, prefixed with the identification code of the call unit in question, on the system cable for receipt by that call unit. This signal is interpreted by the microprocessor 12 of the call unit as an ,nstruction to 3peil a speech chuilnel from the microphone 16 of the call unit to a pair of speech signal conductors of the system cable 6, and thence to the speech equipment of the master unit 5. The person handling the call can thus listen to any sounds originating in the resident's dwelling.To address the resident, the operator presses a TALK button on the master unit keypad 22 which causes a voltage change on the speech control lines of the system cable 6, interpreted by the microprocessor of the call unit as an instruction to reverse the speech path.

This is now open in the direction from the operator to the call unit, enabling the warden to speak to the resident.

By pressing and releasing the TALK switch, the warden may cause alternation between the two speech directions and thus conduct a conversation with the resident, the warden using the microphone and loudspeaker of the call unit into which the master unit is connected at the time. On completion of the conversation, the warden presses a CLEAR button, whereupon a signal is transmitted to the call unit and interpreted as an instruction to close the speech channel, thus terminating the call.

In accordance with the invention, the communication system described has a radio system added thereto. The radio system provides means whereby each resident 8 of the sheltered housing scheme may raise an emergency call without the need to press a button on the call unit or operate an alternative fixed call raising switch, e.g. one of several ceiling mounted pull cord switches located in different rooms of the dwelling, simply by operating a small personal radio transmitter unit 9, worn permanently by the resident or kept in his/her vicinity. The call radio signal transmitted by the transmitter 9, which contains a numerical code particular to the resident concerned, is received by a radio receiver 41 located at a central position on the sheltered housing scheme.The receiver 41 is connected to the system cable 6, and on receipt of a call radio signal, the receiver outputs a signal on the system cable which is received by the control unit 7. The call radio signal includes a numerical identification code that is the same code as that for the call unit 1 of that resident. The call radio signal is then interpreted by the microprocessor 21 in the same way as a call from the call unit and the warden is instructed to initiate an emergency call to the resident concerned.

Rather than use identical codes for a call unit and its radio transmitter these codes may differ (but possibly be related) in order that the warden may receive an indication as to whether an alarm has been raised from a call unit or a radio transmitter.

The radio system also includes a self-test arrangement whereby the control unit 7 incorporates a timer, and has mounted in its vicinity a fixed radio transmitter 43, which may be similar in construction to those carried by the residents. The control unit 7 and the transmitter 43 are electrically interlinked such that the control unit 7, under control of the timer, triggers the transmitter 43 at regular intervals (e.g. every 60 seconds) to transmit a radio signal to be received at the central receiver 40, 41.

The transmitter 43 is programmed to transmit a numerical identification code which when received by the receiver 41 and forwarded on the system cable 6 to the control unit 7 has the effect of resetting the timer in the control unit to zero. Should however the timer not be reset to zero by receipt of this signal from the fixed transmitter 43, the timer continues to run until a predetermined time (e.g. 70 seconds) has elapsed since it was last reset. The microprocessor in the control unit 7 monitors the count of the timer, and when the aforementioned predetermined elapsed time value is reached, gives rise to initiation of a call on the system, the call having an identification code indicating a radio failure.

Hence, should the timer not be reset, for reason of the central receiver failing to respond to a signal from the fixed transmitter, a call is raised on the system to bring the radio failure to the notice of the warden.

Claims (5)

1. An emergency speech communication system for use with a plurality of remote call stations, the system comprising: a master unit having data display means, data entry means and sound transducer means associated therewith; a plurality of call units each for location at a respective call station and having a call raising switch and sound transducer means; transmission means for interconnecting the master unit and the call units for conveying data, control signals and audio signals between the master unit and each call unit; a control unit having electronic control circuitry for controlling the operation of the system; at least one personal radio transmitter unit associated with a respective one of said call units, and operable to issue a call radio signal which is distinctive of said one call unit;; a central radio receiver arranged to receive the call radio signal and connected to the control unit, the control unit being responsive to a received call radio signal to raise a call on the system in the same way as if the call raising switch of said one call unit had been operated; a self-test arrangement provided in the control unit and including a timer operative to initiate a warning signal after a predetermined period unless re-set to zero within that period; a fixed radio transmitter unit linked to the control unit such that the control unit, under the control of the timer, triggers the transmitter unit at regular intervals to issue a test radio signal distinctive of the fixed radio transmitter unit and to be received by the central receiver; the control unit being responsive to a received test radio signal to cause the control unit to re-set the timer to zero; and means provided in the control unit and responsive to the warning signal from the zimmer for initiating a warning call on the system indicative of a failure of the central radio receiver, in the event of the predetermined period expiring without the timer having been re-set to zero.

2. A system according to claim 1 in which a plurality of personal radio transmitter units are provided, each associated with a respective one of the call units.

3. A system according to claim 1 or claim 2 in which each radio transmitter unit is operable to transmit the same numerical identification code to the central unit as the code transmitted by its associated call unit.

4. A system according to any one of the preceding claims in which the fixed radio transmitter unit is of generally similar construction to that of the personal radio transmitter unit.

5. An emergency speech communication system substantially as herein described with reference to the accompanying drawings.