NL2003647C2

NL2003647C2 - Alerting system and method, and send unit and transceiver unit for use in the same.

Info

Publication number: NL2003647C2
Application number: NL2003647A
Authority: NL
Inventors: Serge Kalkhoven
Original assignee: Kadex Holding B V
Priority date: 2009-10-15
Filing date: 2009-10-15
Publication date: 2011-04-18

Description

Alerting system and method, and send unit and transceiver unit for use in the same

The present invention is related to an alerting system 5 and method. It further relates to a send unit and transceiver unit for use in the same.

An alerting system is a system which is capable of monitoring a specific parameter and condition and of generating an alerting message if a predefined threshold 10 pertaining to the parameter or condition is exceeded. An example of such a system is a personal send unit which is carried by a user and which maintains a wireless connection to centrally positioned transceiver unit. In case of an emergency, the user presses an emergency button on the send 15 unit as a result of which a message will be sent to the transceiver. This message contains an identifier of the send unit. Upon receiving the message, the transceiver unit will relay the message to a monitoring unit. The monitoring unit comprises a database having contact information specific for 20 the identifier of the send unit. Such contact information could comprise telephone numbers of people to call in case of an emergency. For instance, in an elderly home, the contact information could comprise telephone or pager numbers of medical personnel, which need to be contacted in 25 case of a medical emergency of the user of the send unit.

A drawback of known systems is that it is difficult for the contacted persons to know the location of the user who initiated the emergency call. This problem could be obviated by incorporating GPS functionality in the send unit, but 30 such a solution is not preferable due to high costs.

Moreover, a translation still has to be made from the GPS coordinates into information useful for the contacted persons .

2

The present invention provides a solution to this problem. According to the invention an alerting system is provided which comprises a send unit having a send unit identifier and a transceiver unit having a transceiver unit 5 identifier. It should be noted that both the send unit identifier and the transceiver unit identifier are preferably implemented in hardware, for instance by programming in the factory. The present invention does not exclude the possibility that these identifiers can be 10 assigned later on, i.e. during use or initialization of the system, by the user or an administrator. In this case, the send and or transceiver unit comprise a memory element in which the identifier can be stored. Before programming, the identifier of the relevant unit is determined by the default 15 value in such memory element.

The alerting system further comprises a monitoring unit having a database which comprises transceiver unit identifier specific geographical information and send unit identifier specific device contact information. Transceiver 20 unit identifier specific geographical information comprises information about the geographical position of the transceiver unit having the specific transceiver unit identifier. Similarly, send unit identifier specific device contact information comprises information how to contact at 25 least one user device which is assigned to the send unit with the specific send unit identifier.

According to the invention, the send unit is arranged for sending a first message to the transceiver unit comprising the send unit identifier and send unit status 30 information. The send unit status information could for instance comprise the status of an emergency button, e.g. pressed or not, or a temperature reading of a thermometer inside the send unit.

3

The transceiver unit is furthermore arranged for sending a second message to the monitoring unit comprising the first message and the transceiver unit identifier. Consequently, the monitoring unit receives the transceiver 5 unit identifier of the transceiver unit sending the second message, as well as the first message comprising the send unit identifier and status information sent from a send unit connected to this transceiver unit.

According to the invention, the monitoring unit is 10 further arranged to communicate an alerting message to a device using the device contact information in dependence of the received send unit status information and the received send unit identifier, wherein the alerting message comprises the geographical information corresponding to the received 15 transceiver unit identifier. After receiving the second message, the monitoring unit will extract the relevant contact information from the database using the received send unit identifier and it will extract the relevant geographical information from the database using the 20 received transceiver unit identifier. The alerting message that is generated by the monitoring unit comprises the geographical information. Using the contact information, one or more user devices are identified, and the alerting message is sent.

25 In the system according to the invention, it is the geographical information of the transceiver unit which is communicated to the user(s) and or device(s) in the contact information. This is advantageous because the position of the transceiver unit is substantially stationary.

30 The alerting system of the present invention is preferably not only capable of sending messages to devices such as mobile phones or personal computers, which are not directly connected to the transceiver unit, but also to 4 other send units that are connected to a transceiver unit of the alerting system. Most often these send units are connected to the same transceiver unit as that which was involved in the aforementioned message transfer. To achieve 5 this effect, the alerting system of the present invention preferably comprises a plurality of send units each having a different send unit identifier. The monitoring unit is then arranged to send a predefined first return message to the transceiver unit in response to receiving the second message 10 and in accordance with the contact information. The predefined first return message comprises at least one send unit identifier corresponding to at least one of the plurality of send units. It further comprises the transceiver unit identifier and a message portion.

15 Accordingly, the transceiver unit is arranged to receive the predefined first return message and to send a second return message to the at least one send unit corresponding to the received at least one send unit identifier, which message comprises the message portion.

20 In an embodiment of the above system, the plurality of send units comprises an emergency unit having an emergency button which is mounted to a wall. In case of an emergency, the emergency button can be pressed after which the emergency unit will act as send unit and send a first 25 message to a transceiver unit. Additional send units are coupled to the lighting system nearby the emergency unit. These additional units are also coupled to the same transceiver unit but need not be. When the monitoring unit receives the second message it may send an alerting message 30 to one or more user devices such as mobile phones, pagers, etc. It may also send a predefined first return message to the emergency unit. An example of such a message could be a simple acknowledgement such that the user who has pressed 5 the button knows that his call for help has been dealt with. Additionally or alternatively, the first return message may be directed to one or more of the additional send units which are coupled to the lighting system. Such a message 5 could comprise a command to switch on the lighting in the neighbourhood of the emergency unit, or to turn on the sprinkler system. As such, and not only limited to this example, the database may further comprise one or more predefined messages per contact in the contact information. 10 The exact message sent may also depend on the second message received. For instance, if the second message indicates a fire, the sent alerting message and or predefined first return message may differ from those sent in case of another emergency .

15 The transceiver unit may be arranged to route messages received from the monitoring unit based on the send unit identifier (s) contained therein. Alternatively, the transceiver unit may broadcast each received message to every send unit it is connected to. In the latter situation, 20 the send units may comprise filtering means to filter out those messages which are directed to them. A specific send unit identifier may be used to indicate that a message should be sent to all send units.

The monitoring unit can be arranged to compare the 25 status information to a predefined threshold and to only send the alerting message when said threshold has been exceeded. For instance, the monitoring unit may only send the alerting message when status information is not empty or when the status information exceeds a certain value. Such 30 comparison can also be performed in the send unit and or transceiver unit. In this case, either unit may refrain from sending the first and or second message or it may modify the status information accordingly, e.g. a "0" in case no 6 dangerous condition exists and a "1" in case there is. The monitoring unit still has to determine and or compare whether a "0" or "1" has been sent, albeit there is no need for predefined values to be stored in the database. It 5 should be obvious to the skilled person that various combinations are possible.

The central database may further comprise a send unit description corresponding to the send unit identifier. Here, the alerting message further comprises the send unit 10 description corresponding to the received send unit identifier. Consequently, the alerting message will state the location of the transceiver unit which is connected to the send unit initiating the alerting message in addition to a description of the send unit.

15 It is advantageous if the monitoring unit is adapted for simultaneous connection to a plurality of transceiver units. Then, the central database comprises geographical information for each of the plurality of transceiver units. This allows a user carrying his send unit to move about 20 without risking loosing contact with a transceiver unit. The send unit and transceiver are preferably arranged to perform authentication prior to establishing the communication link for transferring the first message. The send unit and transceiver unit may further comprise means for allowing 25 transfer of a send unit between different transceiver units. For instance, if a send unit is within range of two transceiver units, the first message may be generated twice. Another option would be to include a transfer protocol in which the send unit is disconnected from one of the 30 transceiver units and connected to the other.

It is further advantageous if the transceiver unit is adapted for simultaneous connection to a plurality of send units, wherein the central database comprises contact 7 information for each of the plurality of send units. Here, each transceiver unit is able to send a plurality of first messages, each message being specific to a particular send unit. When using multiple send units connected to a single 5 transceiver unit, it is preferred to use unique send unit identifiers .

By combining the above measures a system can be obtained in which a plurality of send units is connected to a plurality of transceivers but wherein only a single 10 monitoring unit is used. The central database in this unit then contains the geographical information of the connected transceiver units and the contact information pertaining to the connected send units.

The transceiver unit and the monitoring unit preferably 15 each comprise a network adaptor for establishing an Ethernet connection between them. Such a network adaptor comprises a specific MAC address which is independent of the connection between transceiver unit and send or monitoring unit, contrary to an assigned IP address. A MAC address is 20 specific to the network adaptor used and is even different between two identical adaptors from the same manufactures. Hence, a MAC address can be used to uniquely identify a transceiver unit in the system.

The send unit and transceiver unit preferably each 25 comprise communication means for establishing a short-range wireless connection between them. Examples of such a connection are Bluetooth, MiWi, Zigbee or Z-wave however the present invention may be used with any radio frequency (RF) protocol.

30 It is advantageous if the monitoring unit is accessible by a user for inputting the geographical information per transceiver unit identifier and the contact information per send unit identifier. A user, not necessarily being a user 8 contained in or related to the contact information, can log into the monitoring unit to add, modify, and or delete entries regarding contact information or geographical information. This information is entered with respect to a 5 particular send or transceiver unit identifier.

The send unit can be adapted for sensing an alarm signal emanating from an alarm device and for comparing the received alarm signal to a predefined value, wherein the status message to be sent to the transceiver unit comprises 10 a result of said comparison. An example of an alarm device is a smoke detector. Upon detecting smoke, the detector will generate an alarm signal. This signal can be detected or sensed by the send unit which will compare the received signal with a predefined value. In case of a temperature 15 meter as alarm device, the sensed temperature could be compared to a maximum value. The result of such a comparison, or the received alarm signal itself, is sent to the monitoring unit as part of the status message. In case the status signal comprises the actual received alarm 20 signal, the monitoring unit could be arranged to compare the signal with a predefined threshold.

In case a wired connection is used between the alarm device and the send unit, alarm device and send unit can be integrated into one unit. In one embodiment of the 25 invention, the alerting system comprises a plurality of smoke detectors with integrated send units installed in a home. The transceiver can be integrated with or coupled to a gateway of the home network to enable an Ethernet connection to the monitoring unit. In case of a fire, a resident of the 30 house in question may receive a message stating the location of the transceiver unit and the name of the smoke detector responsible for the alerting message. This is even possible 9 when the resident is not at home, even when he or she is abroad.

In case the alarm device and the send unit are separate units remotely positioned from each other, the send unit can 5 be adapted to sense audio signals or light signals emanating from the alarm device. For instance, the send unit may respond to the typical high frequency sounds and sound pattern generated by a smoke detector in case of an emergency .

10 The monitoring unit preferably comprises an SMS server for sending an SMS message to the device. Such an approach also allows substantially simultaneous distribution of the alerting message to a plurality of devices or users according to the contact information.

15 The send unit and or the transceiver unit are preferably adapted to generate a heartbeat signal and or battery level signal which are incorporated in the first and or second message, or which are sent as dedicated messages to the transceiver unit or monitoring unit, respectively. In 20 that case, the monitoring unit is adapted to compare a received heartbeat signal and or battery level signal to a predefined threshold, and the monitoring unit is arranged to send a further alerting message to a device in accordance with the contact information in dependence of said 25 comparison to said threshold.

A heartbeat signal is a periodic signal used to indicate the presence or status of a unit. For instance, the send unit or transceiver unit may periodically send out an electrical signal or code to the transceiver unit or 30 monitoring unit, respectively. The transceiver unit, but preferably the monitoring unit, will expect this signal as proof of the fact that the relevant unit is connected. To that end, the transceiver unit or the monitoring unit will 10 compare the received heartbeat signal to a predefined threshold, e.g. receive a signal 5 times per hour. In case the threshold is exceeded, a further alerting message may be dispatched by the monitoring unit to a device of which the 5 contact information is stored in the database. Such device could for instance be the cellular phone of the system administrator. The alerting message could for instance be that a transceiver or send unit is no longer connected. In case the transceiver unit is arranged for the above 10 mentioned comparison, a result thereof can be part of the second message. Additionally or alternatively, a battery level signal can be generated. Consequently, an administrator may receive a message that the batteries of a specific transceiver unit or send unit must be charged or 15 replaced.

It is advantageous if the monitoring unit comprises a memory for storing an association between a received send unit identifier and transceiver unit identifier. Consequently, the monitoring unit always has recent 20 information about which send unit is connected to which transceiver unit. Such information is important in case of an emergency evacuation where people are carrying send units. Information can be easily generated regarding the whereabouts of the different people carrying the portable 25 send units.

The present invention further provides an alerting method which comprises the steps of providing a send unit and a transceiver unit, constructing a database within a monitoring unit comprising send unit specific contact 30 information and transceiver unit identifier specific geographical information. The method further comprises sending a first message from the send unit to the transceiver unit, wherein the first message comprises the 11 send unit identifier and a status message of said unit, and receiving the first message and sending a second message comprising the transceiver unit identifier and the first message to the monitoring unit. Subsequently, the relevant 5 contact information is extracted from the database using the received send unit identifier and the relevant geographical information is extracted from the database using the received transceiver unit identifier. An alerting message will be generated comprising the geographical information.

10 This message will be sent to a user device using the extracted contact information.

As mentioned before, an alarm signal emanating from an alarm device can be sensed and compared to a predefined threshold. The first message may be generated as to comprise 15 a result of the comparing.

Additionally or alternatively, a heartbeat signal and or a battery level signal may be generated within the send unit and or the transceiver unit. This signal may be incorporated in the first and or second message or it may be 20 sent as a dedicated message to the transceiver unit or monitoring unit, respectively. The received heartbeat signal and or battery level signal are compared to a predefined threshold, and a further alerting message is generated comprising a result of this comparison. This alerting 25 message is sent to a device in accordance with the contact information stored in the database.

Next, the present invention will be described in more detail using the attached drawings, in which:

Figure 1 illustrates the general principle of the 30 present invention;

Figures 2A and 2B show examples of information stored in the central database; 12

Figure 3 shows a flow graph indicating the content of the various messages throughout the system; and

Figure 4A and 4B show a flow graph indicating the content of messages from the monitoring unit back to 5 multiple send units and a corresponding database entry, respectively.

Figure 1 illustrates a monitoring unit 1 comprising a central database 2 and an SMS and email server 3. This server is capable of sending out SMS messages or email 10 messages to one or more persons or devices.

Monitoring unit 1 is connected to two transceiver units 4, 5, which are each connected to different send units 6, 7, 8, 9. Each send unit is associated with a different user or device 10 which should be contacted in case of an emergency, 15 as illustrated by the dotted line. The information required to identify these users or devices 10 is stored in central database 2. An example of such information is provided in figures 2A and 2B.

Each send unit has a unique send unit identifier 11, as 20 shown in figure 2A. A description 12 can be entered in the database for each send unit identifier 11 allowing for convenient recognition as identifier 11 is mostly a hexadecimal number. In addition, contact information 13 is stored containing information how to reach user(s) or 25 device(s) 10 in case of an emergency. Several different types of contact information, e.g. fax number, email address, phone number, etc. may be stored. Multiple contact users or devices may be assigned to a single send unit.

Figure 2B illustrates the geographical location 30 information 14 which is stored in the database for each transceiver unit identifier 15. Here, an association is stored between the transceiver unit identifier 15, e.g. a 13 MAC address, and the home address where this transceiver unit is installed.

In figure 3, the message flow is shown between the various components in the system. Here, send unit 6 5 ("kitchen") is connected to a thermometer 16 via a wired connection. Thermometer 16 measures the temperature in the kitchen to be 29.5 degrees centigrade. This value is communicated to send unit 6 which incorporates it in the status information part 17 of the first message 18. First 10 message 18 is sent to transceiver unit 4. This unit adds his identifier and sends the combination as the second message 19 to monitoring unit 1.

Communication between send unit 6 and transceiver unit 4 is via a wireless RF connection, such as Bluetooth. This 15 eliminates the need for excessive wiring in the home.

Communication between transceiver unit 4 and monitoring unit 1 is over the internet via an Ethernet connection. Consequently, monitoring unit 1 need not be within the same LAN or even within the same country. A further advantage is 20 that monitoring unit 1 can be used for multiple transceiver units 4 and send units 6 belonging to different homes, networks, companies, or countries.

Upon receiving second message 19, monitoring unit 1 will extract the required information from database 2.

25 Additionally, it will compare the received temperature value with predefined threshold values. Examples of threshold values are illustrated in figure 2A. For send unit 6, a threshold value of 25 degrees centigrade is stored in database 2 which indicates that monitoring unit 1 will 30 generate and send an alerting message to the predefined contact users or devices 10 in accordance with the contact information for send unit 6. Other examples of threshold information could be the presence or non-presence of a 14 detection of an alarm signal, e.g. an audible signal from a smoke detector, a humidity level, or the pressing or nonpressing of an emergency button on a send unit. The comparison can also be performed in a send unit or 5 transceiver unit. In that case, the mere presence of the status information could trigger the generating and sending of an alerting message by the monitoring unit.

After the alerting message has been generated, monitoring unit 1 will send an SMS message 20 to user A and 10 user B using the contact information stored in database 2. The contents of this message comprise the geographical location of transceiver unit 4 and the description of send unit 6. Additionally, text may be added such as the status message received (T=29.5).

15 In figure 4A, monitoring unit 1 has just received a second message indicating a fire emergency. Consequently, monitoring unit 1 will, based on the data in the database, send two messages to two different send units. One of those send units is the send unit from which the first message 20 emanated. The other unit is a unit connected to a sprinkler system near the former send unit. The messages are preferably predefined. In other words, based on the second message received from the first send unit by the monitoring unit, return messages are created and sent to the predefined 25 contacts in accordance with the contact information. As such, the database not only comprises contact information but also protocols describing the actions or messages relevant to a specific message from a particular send unit. This information can be stored send unit specific.

30 Referring back to figure 4A, both messages 21, 22 are sent to transceiver unit 4. Each message comprises a message portion 23, the transceiver unit identifier, and the send unit identifier. After receiving these messages, transceiver 15 unit 4 will direct messages 21, 22 to the relevant send units 6, 24. It will also send an SMS message 20 to contact A. Message 21 to send unit 6 comprises an acknowledgement message or a similar command. For instance, a LED indicator 5 on send unit 6 may start blinking indicating that the emergency is being dealt with. Message 22 comprises a command for turning on the sprinkler system. Send unit 24 is connected to a sprinkler system such that it is able to control that system. A command interpreter in send unit 24 10 is able to extract the command from the message and to convert such a command into a controlling signal for the sprinkler system.

Figure 4B shows a corresponding database entry. For send unit 6, contact information 13 is provided which 15 includes the send unit identifier of send unit 24 as well as the identifier of send unit 6. The shown entry only relates to the situation when the second message 25 is related to a fire emergency. A return message 26 is generated per contact in the contact information 13. For contact A, a SMS text 20 message 20 is sent instead of the return message. Threshold information can be used to determine whether or not to send the message. This can be advantageous if the second message contains a value such as in figure 2A.

It should be noted that the database entry can also 25 comprise further information regarding the SMS message to the various contacts. In fact, a complete protocol can be established describing who/what to contact, how a message should look like or what the content should be, under which circumstances should the message be sent, etc.

30 The transceiver unit is generally installed behind a private Internet router firewall via a NAT protocol. To make connection to the transceiver unit from the Internet possible, the transceiver unit has to initiate the 16 connection. The transceiver unit is doing this by sending a heartbeat message on a regular interval. This message can be part of the second message or it can be a dedicated message from the transceiver unit to the monitoring unit. The 5 monitoring unit is then capable of sending a command to the transceiver unit within a certain time of receiving the heartbeat message. With this protocol the private Internet router does not need to be configured.

After restart or power on the transceiver unit 10 automatically starts sending the heartbeat message to the monitoring unit of which the address is stored in non volatile memory on the transceiver unit.

The heartbeat message contains the transceiver unit MAC address and heartbeat interval. There are two heartbeat 15 interval times stored in non volatile memory. One is the default (HB), this is used after restart or power-up. The second one is the heartbeat event (HBE) interval. The transceiver unit automatically switches over to the heartbeat event timing (HBE), after a message from a send 20 unit is received and send to the monitoring unit.

The transceiver unit keeps on using the heartbeat event timing (HBE) until it receives a new heartbeat value (HB) from the monitoring unit. This new heartbeat value (HB) is then used as the new default heartbeat (HB). When a message 25 is again received from a send unit and forwarded to the monitoring unit, the transceiver unit switches again to the HBE.

All communication is preferably done by TCP/IP. The connection is checked with a heartbeat message. All 30 communication (heartbeats and data) is done through port 80. Each message from a send unit is forwarded to the monitoring unit and the transceiver unit waits for a response. If there is no response from the monitoring unit within a predefined 17 retry time interval, the transceiver unit will re-transmit this message on this time interval forever, until it receives an answer. The retry time interval is stored in the transceiver unit non volatile memory.

5 Each message contains at least the transceiver unit identifier, e.g. the MAC address, and preferably a message identification number and a message age. The message identification number is a unigue number (within a certain time) to identify a new message. This identification number 10 is unigue of each message type and not for all messages e.g. the identification number for a dedicated heartbeat message can be the same as for a first or second message.

The message age is a value in seconds which indicates how old the message is. For example, when a message is sent 15 for the first time by the transceiver unit to the monitoring unit, the age is '0'. If there is no response received by the transceiver unit within the timeout (e.g. 34 seconds), the transceiver unit will re-transmit the message. The retransmitted message contains the same identification number 20 and data, but with the age of 34 seconds. The monitoring unit can determine based on the message age if this message is still valid to process. The identification number can also be used to detect duplicated messages (e.g. when an answer is not received)

25 The transceiver unit gets its IP address through a DHCP

server at start-up. If no DHCP server is available, it preferably tries endlessly getting one.

While getting the IP address from the DHCP server, it submits a DHCP name to the DHCP server. The DHCP server has 30 to submit this name plus the IP address to the DNS server. The transceiver unit is reachable through this name.

It should be obvious for the skilled person having read the description with the accompanying drawings that various 5 18 modifications are possible without departing from the scope of the invention which is defined by the appended claims.

Claims

A warning system comprising: a transmitting unit provided with a transmitting unit 5 identifier; a sending / receiving unit provided with a sending / receiving unit identifier; and a control unit provided with a database comprising transmitting / receiving unit identifier specific geographical information and transmitting unit identifier specific device contact information; wherein the sending unit is adapted to send a first message to the sending / receiving unit including the sending unit identifier and sending unit status information, and wherein the sending / receiving unit is arranged to send a second message to the control unit comprising the first message and the send / receive unit identifier, the control unit being further adapted to communicate a warning message to a device using the device contact information depending on the received send unit status information and the received send unit identifier, the warning message comprising the geographic information corresponding to the received send / receive unit identifier.

2. Warning system according to claim 1, comprising a plurality of said transmitting units each provided with a different transmitting unit identifier, the control unit being arranged for sending a predetermined first return message to said transmitting / receiving unit in response to receiving said second message and in accordance with said contact information, said predetermined first return message comprising at least one sending unit identifier corresponding to at least one of said plurality of sending units, the transmit / receive unit identifier, and a message portion, said transmit / receive unit being arranged to receive said predetermined first return message and to send a second return message to the at least one transmitting unit corresponding to the received at least one transmitting unit 10 identifier, which message it includes the message portion.

3. Warning system according to claim 1 or 2, wherein the control unit is adapted to compare the status information with a predetermined threshold and to only send the warning message if said threshold is exceeded.

A warning system according to any of the preceding claims, wherein the central database further comprises a transmitter unit description corresponding to the transmitter unit identifier, said warning message further comprising the transmitter unit description corresponding to the received transmitter unit identifier.

5. Warning system according to any of the preceding claims, wherein the control unit is adapted for simultaneous connection to a plurality of transmit / receive units, the central database comprising geographic information for each of the plurality of transmit / receive units.

6. Warning system according to any of the preceding claims, wherein the transmitting / receiving unit is adapted for simultaneous connection with a plurality of transmitting units, wherein the central database comprises contact information for each of the plurality of transmitting units.

7. Warning system as claimed in any of the foregoing claims, wherein the sending / receiving unit and the control unit each comprise a network adapter for establishing an Ethernet connection between them, and wherein the sending / receiving unit identifier has a MAC address includes network adapter corresponding to the transmit / receive unit.

8. Warning system as claimed in any of the foregoing claims, wherein the transmitting unit and the transmitting / receiving unit each comprise communication means for establishing a short-distance wireless connection between them.

9. Warning system as claimed in any of the foregoing claims, wherein the control unit is accessible to a user for inputting said geographical information per transmitting / receiving unit identifier and said contact information per transmitting unit identifier.

10. Warning system according to one of the preceding claims, wherein the transmitting unit is adapted to detect an alarm signal from an alarm device and to compare the received alarm signal with a predetermined value, wherein it is sent to the transmitting / receiving unit message to be sent includes a result of said comparison.

The warning system of claim 10, wherein the transmitting unit and the alarm device are provided with a wired connection between them and wherein they are integrated into one unit.

12. Warning system according to claim 10, wherein the transmitting unit is adapted to detect audio signals or light signals from said alarm device.

13. Warning system according to any of the preceding claims, wherein the transmitting unit and whether the transmitting / receiving unit are adapted to generate a heartbeat signal and or a battery level signal incorporated in the first and or the second message or which when individual messages are respectively sent to the transmit / receive unit or control unit, said control unit being adapted to compare a received heart rate signal and / or battery level signal with a predetermined threshold, and wherein the control unit is arranged for sending a further warning message to a device in accordance with said contact information in dependence on said comparison with said threshold.

14. A warning system according to any one of the preceding claims, wherein the control unit comprises a memory for storing an association between a received send unit identifier and send / receive unit identifier.

A warning method comprising: providing a sending unit and a sending / receiving unit; constructing a database within a control unit comprising contact information coupled to an identifier of the sending unit and geographic unit coupled to an identifier of the sending / receiving unit; sending a first message from the sending unit 30 to the sending / receiving unit, said first message comprising the sending unit identifier and a status message from said unit; receiving the first message and sending a second message including the transmit / receive unit identifier and the first message to the control unit; Extracting the relevant contact information from the database using the received transmission unit identifier; extracting the relevant geographic information from the database using the received transmit / receive unit identifier; generating a warning message including the geographic information; sending the generated warning message to a user device using the extracted contact information.

The warning method of claim 15, further comprising: detecting an alarm signal from an alarm device; 20 comparing the received alarm signal with a predetermined threshold; generating the first message including a result of said comparing.

The warning method of claim 15 or 16, further comprising: generating a heart rate signal and or a battery level signal within the transmitting unit and or the transmitting / receiving unit; incorporating the heart rate signal and or battery level signal in the first and or second message or sending the heart rate signal and or battery level signal as a separate message respectively to the transmitting / receiving unit or control unit; receiving the heart rate signal and / or battery level signal; comparing the received heart rate signal and / or battery level signal with a predetermined threshold; 5 generating a further warning message including a result of said comparing; sending the generated further warning message to a device in accordance with said contact information.

A transmitting unit as defined in any one of the preceding claims 1-14.

A transmitting / receiving unit as defined in any one of the preceding claims 1-14. 2003647