FR2578993A1 - METHOD FOR ENSURING MONITORING OF PERSONS AND / OR PROPERTY AND SYSTEM FOR IMPLEMENTING SAID METHOD - Google Patents

Abstract

THE INVENTION RELATES TO A METHOD AND TO A SYSTEM FOR MONITORING GOODS AND OR PERSONS BY TRIGGERING AT LEAST ONE ALARM ON THE OCCURRENCE OF PARTICULAR EVENTS. THIS PROCESS IS CHARACTERIZED IN THAT FOLLOWING THE DETECTION OF A DETERMINED EVENT, A UC CENTRAL UNIT IDENTIFIES THE DETECTOR (S) D, D EXCITED IN ORDER TO COMMAND THE TRIP OF AT LEAST ONE S, B, L, Q DEVICE D ' ALARM ACCORDING TO THE DETECTOR (S) EXCITED. IN ADDITION, DIFFERENT MEANS OF MONITORING ALLOW THE USER TO INFORM THE USER OF THE EVENT ORIGIN OF THE ALARM.

Description

257899f

SIL.BOU

  METHOD FOR PROVIDING MONITORING

OF PERSONS AND / OR PROPERTY

  AND SYSTEM FOR IMPLEMENTING SAID METHOD

  The invention relates to a method and a security system for monitoring property and / or people by triggering at least one alarm at the occurrence

special events.

  This system is more particularly intended to be used for the surveillance of a dwelling, its dependencies and certain properties, and possibly for the surveillance of persons who are

find nearby.

  There are many so-called security systems for monitoring homes or property. These systems include a central unit connected to detectors and an alarm device. As soon as a detector is energized, the control unit triggers the alarm. The trigger may be due to an intrusion, or even to a

  abnormal event such as, for example, leakage of water, gas.

  For this, each detector is specialized for a given event.

  However, existing systems have

  vantages. A central unit is usually connected to several detectors, but when a detector is excited, only one type of alarm is triggered, and it is not possible to know which detector has

  generated the alarm, and therefore the origin of the alarm.

  Thus, it is conceivable that it is not possible to use the same alarm to provide both monitoring against intrusions and monitoring of internal events such as water leaks, etc. Indeed, the purpose of a surveillance is to scare a possible intruder: in this case the unit must trigger an alarm such as a siren. On the other hand, the monitoring of internal events implies that only the occupants of the dwelling are informed: it is not

  necessary to use a siren placed outside.

  Also, when the system is used for intrusion detection, it must be armed when the user leaves and disarmed when returning. However, arming and disarmament are carried out at the central unit, which is usually placed in the safest place in the area to be protected, that is to say normally in the center of this zone. In this case, a time delay must be provided to allow the outputs and the returns without the system being triggered. For this, the detector placed near the usual entrance is timed, and it is therefore possible for an intruder to successfully enter the premises and steal some objects before the

triggering the alarm.

  Finally, the implementation of these systems involves wiring between the detectors and the central, and between the central and the

  alarms, which is expensive and not always aesthetic.

  The method of the invention does not have these disadvantages.

  According to the invention, a method for ensuring the security and surveillance of persons and / or property by triggering an alarm by a central unit in communication with the

  least two detectors is characterized in that before the

  alarm, the central unit identifies the detector (s) which have been excited, and in that, several different alarms can be triggered by the central unit, the latter triggers it.

  one or the other or more depending on the detector (s) excited.

  Thus, thanks to this process, we identify and we know the cause

  or the causes of triggering one or more alarms.

  According to another characteristic of the method of the invention, the communication between the detectors and the central unit is carried out

  without there being physical connection between a detector and the central.

  A system for carrying out the method of the invention is characterized in that each detector is connected to a transmitter comprising a coding unit and a transmitter emitting a coded signal enabling its identification, in that the central unit comprises a receiver , a received signal processing unit and a programming unit, and means for triggering

different alarm devices.

  In a preferred embodiment of the system, the unit.

  central comprises encoding means and the alarm devices comprise a receiver associated with a decoder. Each receiver is assigned a particular code and the programming unit of the central unit allows in particular to designate which device

  alarm will be triggered when one or more detectors

The culprits will have been excited.

  In this embodiment, the central unit is connected directly

  the electrical sector of the place where it is located and

  has a signal transmitter on the mains wires.

  This transmitter sends coded signals to the mains. Alarm receivers are also connected to the mains and feature

a receiver of these signals.

  When a decoder detects a signal corresponding to its

  code, the associated alarm is triggered.

  Other features and advantages of the invention appear

  will be with the description of some embodiments that will

  follow, made with reference to the appended figures: - Figure 1 is a block diagram of a system for implementing the method; FIG. 2 is a block diagram of a device associated with a detector; FIG. 3 is a block diagram of a device associated with an alarm;

  FIG. 4 is a complete block diagram of the system.

  In Figure 1, there is shown the block diagram of a basic system for carrying out the method of the invention. Two

  detectors D1 and D2 are respectively associated with two transmitters

T1 and T2.

  The detectors may be volumetric radars, infrared detectors, magnetic detectors, or probing systems that close an electrical circuit, or all

other known types.

  In one embodiment, the transmitters T1, T2 comprise

  a transmitter associated with an antenna 11, 12, a microprocessor for encoding signals and a rechargeable battery or rechargeable battery. Its size is small and it can be easily carried by a person. In this case, it is possible, for example, to use it as a personal monitoring device, either as a nurse-guard or anti-aggression device or medical assistance. For this, the control of the emission is done using a

  switch placed on the housing containing the transmitter.

  This figure also shows two devices Pt1 and Pt2 called gatekeepers. These devices include a keyboard consisting of T keys that enter a code. The interior of a gatekeeper comprises a transmitter associated with an antenna 14, 15. The role of the gatekeeper is to allow to arm or disarm totally

  or partially remote UC CPU. Thanks to this arrangement

  However, no intrusion detector requires a timer.

  It is therefore no longer possible to approach the central unit without

  to have it disarmed, which increases the reliability of the system.

  The central unit UC comprises a reception antenna 13,

  a processing unit Tr3 associated with a program device

  Pr3, a transmission device E3 of the control signals of the

alarm devices.

  These different elements are powered by an A3 circuit connected to the domestic alternative network. In a variant, a

backup battery is provided.

  In the preferred embodiment shown in this FIG. 1, the emitter E3 for the control of the alarm devices

  emits directly to the EL electrical sector.

  Thus, no additional wiring is required to install the entire system. Alarm devices are everything

  simply plugged into the electrical outlets of the protected area.

  Each alarm device consists of a receiver

alarm and a means of alarm.

  In the example, four receivers RAi, RA2, RA3, RA4 are respectively connected to the mains by taps P'1, P2, P3, P4 and to the alarm means via the outputs S1, S2, 53, S4. The various means can be a siren S, a chime B, a lamp or a projector L or any other means O. The operation is as follows: With the programming device Pr3 of the central unit, the user determines the the alarm receivers that will be

  activated in response to transmission by one or more transmitters

determined.

  In another mode, at least two transmitters can

  be associated with the same means of alarm.

  Thus, for example, the whole can be programmed so that the detection of an event by the detector D1 causes the triggering of the siren S and the lighting of a projector L thanks

to RA1 and RA3 receivers.

  The set can be programmed so that the same alarm, for example the siren S is triggered following detection by the

  detector D1 or by the detector D2.

  In one embodiment, it is also provided that several detectors are connected to the same transmitter, it is thus possible, for example, to monitor a room by placing a

  detector on each door or window and linking them to a trans-

single transmitter.

  The programming keyboard is also used for

  grammar a system access code, code that will be dialed on one of the Pt1 or Pt2 gatekeepers to arm or disarm the remote central unit. Gatekeepers can also be used to remotely control automation devices such as door openings and lamp ignitions, using special codes. Receivers

  specials allow the control of these automatisms.

  In variants, it is intended to carry portable porters and / or fixed door operators. A fixed gatekeeper can, for example

Z578993

  be permanently attached near the main entrance. On the latter, in a variant, there is a doorbell button visitors who, when pressed, generates a special message that will trigger for example a bell. No wiring is therefore needed to connect the bell to its triggering means. Figure 2 shows the block diagram of a transmitter Ti. A transmitter consists of a microprocessor MP1, a transmitter E1 connected to an output of the microprocessor and an antenna 13, and means II and G1 for assigning an identification code to the transmitter, which code is processed by the microprocessor MPI. We

  also provides a battery B1 to power the components.

  In a preferred embodiment, the means Il and G1 consist of two series of numbered dials. The first series

  It comprises, in the example, two wheels M11 and M12 which allow

  try to discern two transmitters belonging to the same

  group. The same group is made up of all the trans-

  transmitters intended to transmit to the same central unit. One group is discerned by the second series G1 which includes, in

  the example three wheels M21, M22, M23. Thus, all trans-

  transmitters associated with the same unit will have the same group code.

  This distinction makes it possible to prevent the information

  for a central unit to be processed by the central unit of a close neighbor who possesses the same system, and who would

  in the range of the transmitter.

  The microprocessor MPI has several other inputs 21, 22, 23, 24, 25 on which the signals can be injected during a detection. One entry or the other is used depending on the type of

detector used.

  It is thus possible to use at least one interrupt type input, that is to say an input that reacts on a rising edge

  or descending current or voltage.

  Infrared or radar type detectors for example

  will be connected to such entries.

  It is possible to use inputs that react to a

change of state.

  Magnetic detectors, for example, will be connected to

  such entries. Thus, when arming the system, the micro-

  processor will take into account the state of the input. If a change

  state occurs, a show will take place. This possibility is particularly

  interestingly, for example in the case where it is desired to consider that the normal state of a door is its open state and

  that its closing must trigger an alarm.

  In the example, a first detector D1 is connected to an input

  21. A second detector D1i is connected to another input 24.

  The first detector D1 is the detector of the event for

  which the transmitter is used, that is, an ultra-high speed radar

  sound, either an infrared radar or a water leak sensor, etc. A second DiI detector is actually a security detector

anti-theft transmitter T1.

  The transmitter T1 is in the form of a housing. The coding wheels are located inside this case. It is important that this coding can not be modified by a third party, without the knowledge of the user of the system. Thus, this detector D11 is for example a simple switch connected to an input of

interrupt type.

  The opening of the transmitter box will result in a broadcast

  immediate flight signal to the central unit.

  Figure 3 shows the block diagram of an alarm receiver RA1. It comprises a power supply circuit 31 connected to the sector by the P1 socket. This circuit transforms the alternating current

  DC power supply of the various components.

  A mains interface circuit 32 is connected to the mains by the jack P1. Its role is to filter the frequency of the sector and to extract the carrier of the signal emitted by the emitter E3 of the central unit

(figure 1).

  At the output of the interface is a demodulator circuit 33 and a shaping circuit 34 for making the signals usable by a microprocessor 35. For this the output of the shaping circuit is connected to an input of the microprocessor 35. On two other inputs are connected two coding means G2 and 12 constituted, in the embodiment of the figure, two

series of wheels.

  A first means G2 makes it possible to assign the group code to wheels M31, MN32, M33 and the second 12 makes it possible to assign the

  receiver code with M41 and M42 dials.

  The microprocessor is then connected to a power circuit

  36 which feeds the alarm by its output terminals SI.

  In embodiments, special receivers are provided which have a built-in sound generator, such as a

  ringtone, a nurse call tone or whatever.

  Figure 4 presents a complete overview of the system

  including other variants and additional features.

  The system consists of several detectors DI, D2, ... Dn associated with several transmitters T1, T2, ... Tn such as those

described in Figure 2.

  Two gate devices Pt1 and Pt2 are shown. The central unit UC is powered by an integrated power supply A3 connected to the alternative EL network. A backup battery is also

  planned to power the central unit.

  For the sake of lightening the figure, the connections between the food

  A3 and the other elements of the CPU were not represented. The central unit comprises a reception circuit R3 associated with an antenna 13 for receiving the messages transmitted by the transmitters or the gatekeepers. This circuit is connected to the unit of

  Tr3 treatment carried out, preferably, using a micro-

  processor. A programming device Pr3, of the processing unit consisting for example of a keyboard Pr30 is connected to a

  other of this processing unit.

  A3 transmitter signals to alarm receivers

  PA1, PA2, PAn is connected to an output of the processing unit.

  In the embodiment, the code of the receiver to be

  mander is produced by the processing unit. For this, the sector transmitter includes an oscillator that modulates the transmitted signal. In one embodiment, the system is arranged so that emissions take place from the central unit only when a

alarm must be triggered.

  The output of the transmitter E3 is connected to the power supply sector EL

  tation via an interface circuit (not shown) which allows the superimposed frequency modulated information to be superimposed on the sector. Another output of the processing unit Tr3 is connected to a voice synthesizer circuit Sv3 which itself is connected, on the one hand, to a loudspeaker HP3 integrated in the casing of the central unit, on the other hand to a C3 telephone control circuit which puts the circuit Sv3 of

  voice synthesis in connection with the PTT telephone network.

  According to the programming of the Central Unit, this

  ration, in case of absence of the owner, to telephone a

  message synthesized at one or more predetermined numbers,

the event.

  The voice synthesis circuit Sv3 is finally connected to a radio frequency transmitter HF3 for transmitting messages to RF3 receivers, which can be used as alarm devices or

  anti-intrusion warning, or service.

  In the case where several receivers are part of the system,

  It is possible to send the messages on one or the other or all.

  Each RF3 receiver has an identification code.

  When a synthesized message is to be sent to a receiver,

  determined code, the corresponding code is issued, which allows the

commissioning said receiver.

  The central unit also comprises display means

  and viewing the state of the system. In a mode of realization

  the means of display and visualization consist of

  LEDs and alphanumeric displays.

  These means have a dual function: they allow the control of the system when it is in a standby state, and when an event occurs, as well as the help with the programming, in

  complement of the speech synthesis circuit.

  In another variant, an Im3 printer is provided to memorize the events that may have occurred during the absence of the user. The operation of the system is as follows: when the detectors, transmitters, the central unit and the alarm receivers are in place, the user assigns the same group number to all the transmitters T and the receivers RA, at

  using the group encoding means G1, G2.

  Then, it identifies the transmitters and the receivers, within the group, using the means of coding identifier Il, 12 'Then, the user programs the central unit UC thanks to the keyboard

  Pr30 to determine which alarm will be triggered.

  when a particular detector has been excited.

  It is possible for a user to assign to several RA alarm receivers the same identification code. In this case, when a signal corresponding to this identification code is transmitted, all receivers affected by this code will be excited. Since each receiver can be connected to a different alarm, it is possible in this way to trigger several alarms following a single detection. Thus, when a detector is excited, several

  Separate alarms can be triggered.

  In addition, it is possible to trigger the same alarm or the same series of alarms following the detection of events by

several different detectors.

  In this case, the user will know the origin of the alarm in

  consulting the display unit V3 and / or the printer Im3.

  The programming makes it possible, in response to a detection by a given detector, to trigger one or more alarms associated with the different AR alarm receivers, and / or the transmission of a synthesized message on one of the high RF3 receivers. frequency and / or to a subscriber on the telephone via the PTT network. If an alarm is triggered following an attempted theft of a

  transmitter, the user is also informed.

  Similarly, the microprocessor MP1 associated with a transmitter

  allows, in one variant, to check the state of the battery B1 of food

  tation and to verify that, in the case where the associated detector D1 or D2 or Dn requires a power supply by the sector, the sector is

  present: this is the case for example infrared detectors.

  In one embodiment, the state of the cell is tested by counting transmitter emissions. At each emission, a counter is incremented. During the realization of the transmitter, knowing the components used, it is easy to know the

  current which will be consumed at each emission and therefore of prede-

  end the number of emissions it will take to use the stack.

  Thus, when the number of transmissions reaches a given value, a message is sent to the central unit to inform

  the user that it is time to change the battery.

  In a variant, there is provided a circuit for testing the charge remaining in the battery. When the load becomes less than one

  given value, a message is sent to the central unit.

  The message indicating that it is time to change the battery is transmitted by the printer and / or by the display and / or by the circuit of

vocal synthesis.

  In one embodiment, the microprocessor MPI of a transmitter is programmed to transmit to the associated emitter E3 a code comprising all the data necessary for the processing by the microprocessor Tr3 of the central unit. The code consists of several elements, transmitted as bits,

when an event occurs.

  A first series of four bits has three bits set to 0 to inform the central unit of the emission. The fourth bit is

  set to I when the transmitter is torn off its support, ie

  say when the detector D11 of Figure 2 changes state.

  This fourth bit is reset to 0 when the transmitter

  is replaced on its support or after a battery change.

  Then a series of group bits are sent which correspond to the group code of the transmitter; this code is entered thanks to the wheels M21, M22, M23 group code means G1 of the

figure 2.

  Another series of bits makes it possible to transmit the identification code of the transmitter within the group; it is the code entered thanks to the wheels M iet MI2 coding means

identification number II of Figure 2.

  Then comes an alarm bit which is set when an alarm is to be triggered, ie when the associated detector is

  excited or when the transmitter is stolen.

  Another series of bits makes it possible to obtain indications on the state of the stack: one of these bits is set to I when a number

  determined emissions is achieved.

  The central unit then informs the user.

  This series also includes a bit that is set to I when the sector disappears, whereas it is necessary to feed the

detector connected to the transmitter.

  Two other bits are the images of the inputs reacting to the

change of state.

  Finally a series of bits called "Checksum" allows to verify

the validity of the message transmitted.

  In one embodiment, it is intended to periodically check

  the presence of various transmitters. For this, each transmitter sends a presence message corresponding to the state

current of his entries.

  In case of non-reception by the central unit of such a message, in the time interval considered, the absence will be indicated under

  message on the lm3 printer, and / or on the display unit.

  V3 display and / or as a sound message to the HP3 speaker.

  This periodic check can be done for example

every two hours or so.

  In one embodiment, it is intended to assign to

  transmitters associated with specialized detectors an identification code

  constant fication. In this way, when the central unit receives a message from one of these detectors, the microprocessor Tr3 instructs the speech synthesis circuit Sv3 to send a message via the loudspeaker HP3 to indicate to the user

  the origin of the failure. In case of absence, the message of failure

  launches can be transmitted by telephone to a specific subscriber.

  This is the case for example when a water leak or even

  prolonged freezing of a freezer are detected.

  The same applies to transmitters associated with vehicle intrusion detectors, nurse transmitters, medical assistance, and so on. In one variant, it is expected that specialized receivers are controlled by specialized detectors: for example, the detection of a water leak results in the control of a control valve.

closing of the water supply.

  The programming pad Pr3 of the central processing unit UC is also used to enter a system access code, which code must be formed from the gatekeepers Pt1 and Pt2 to arm and

disarm the alarms.

  In another variant, provision is made for the possibility that a part

  the system is armed, while another is disarmed.

  In another embodiment, it is intended to divide the area

monitored in several areas.

  When the transmitters are in place, they are assigned, by programming, a zone number. In this case, the user chooses

* to supervise an area and / or others.

  Indeed, there are areas that need to be continuously monitored whether the user is present or not, while others

  should only be supervised at night and / or when absent.

  This is for example the case of dependencies that must be

  constantly monitored while the dwelling is not to be over-

  vigil in case of absence or night.

  In this case, rather than programming the armament of each

  transmitter one by one, we do not program, once the trans-

  transmitters are assigned to their area, whether the surveillance status or not

  from each zone, which is much faster.

  In a variant, provision is made for the possibility of ensuring the non-supervision of one zone or the other during intervals of

  given times that can be repetitive.

  Indeed, the microprocessor Tr3 of the central unit UC has an internal clock. In this case, the clock is used to

allow this programming. So, for example, in the case where the system is used to ensure the

  surveillance of a store, it can be considered that the reserve is in itself an area. If, for example, the deliverymen go on fixed days on given days, it is thus possible to cease the surveillance of the reserve to ensure the supply on the expected days of delivery.

  In one variant, provision is made for

  all areas, but to trigger different alarms depending on whether one is in day or night configuration, by

example.

  The programming keyboard is still used to make active or inactive the C3 telephone control circuit for sending messages to specific subscribers. This circuit can

  be made active or inactive whether the user is present or not.

  When the circuit is active, as soon as an abnormal event detection is made, the first telephone number stored in the subscriber bank is dialed. In case of no answer, after a certain number of rings, or line occupation, the

  second number is composed and so on.

  When the subscriber answers, a synthesized message cor-

  spawning at the detected event is emitted. If the subscriber hangs up before the end of the message, then the number is automatically redialed

and the rebroadcast message.

  For security purposes, it is expected that a message can be broadcast at least twice in case the subscriber does not understand it.

the first time.

  Preferably, provision is made for the possibility of three broadcasts in succession. At the end of the third broadcast, the line is automatically cut off by the central unit, whether the subscriber hangs up or not. In one embodiment, if the subscriber hangs up before the end

  the second or third broadcast, the number is not redialed.

  Indeed, it is considered that if he hangs up after the end of the first

  diffusion, this means that he has assimilated the message.

  In one embodiment, it is expected that during programming, the user memorizes his name using the alphabetical keys of the keyboard Pr3. This allows, when a message is sent by telephone, to make known to the recipient

the origin of the message.

  In this case, at the end of the message, the speech synthesis circuit

spell the name of the user.

  The message has for example this texture: "Intrusion at

  sir x.y.z "or" Water leak at Mrs. a.b.c. ".

  The first part of the message depends on the program

  the detected problem and the second one, which is spelled out, is

to the identity of the user.

  The voice synthesis circuit Sv3 thus has a bank of

first parts of messages.

  In one embodiment, service messages are provided that are output from the HP3 speaker to aid programming. In a variant, different alarm levels are provided.

depending on the event to be detected.

  If several transmitters associated with detectors for events of different degrees must cause the triggering of the same alarm, in case of triggering of said alarm, the display unit V3 displays the degree, for example, of the alarm. help from

lights of different colors.

  Also the armed or disarmed state of one zone or the other is

  visualized using means such as visualization LEDs.

Claims (23)

  A method for monitoring persons and / or property and triggering one or more alarms following detection of an event determined by one or more detectors in communication with a central unit, characterized in that a plurality of detectors and several alarm devices being in communication with the central unit, the central unit identifies the   detectors that have been excited to control the trigger   at least one alarm device according to the detectors were excited.   2. Method according to claim 1, characterized in that a   same alarm or series of alarms that can be triggered   different events, the central unit informs the user of   the nature of the events causing the alarm.   3. System for carrying out the method according to claim 1, characterized in that each detector (D1, D2, Dn) is connected to a transmitter (T1, T2, Tn) comprising identification means (G1, II). ) and a transmitter (E1) transmitting a coded signal enabling its identification by the central unit, and in that the central unit (UC) comprises a receiver (R3) of the signals transmitted by the transmitters, a processing unit (Tr3 ) of these signals, a programming unit (Pr3) and means for triggering different alarm devices.   4. System according to claim 3, characterized in that it comprises alarm receivers (RA1, RA2, RAn) connected to alarm devices (S, B, L, Q) different, and in that each alarm receiver has identification means to distinguish it from the others and in that the central unit (CPU) is arranged to be able to trigger either an alarm device or   the other through the associated receiver.   5. System according to claim 4, characterized in that the   means for identifying an alarm receiver (AR) are   encoding systems (G2, I2), and that the central unit (CPU) generates coded signals and that an alarm receiver has means (35) for analyzing the signals transmitted by the central unit (UC) and trigger the associated alarm when the analyzed signal matches to his own code.   6. System according to claim 3, characterized in that the central unit (UC) has a speech synthesis circuit (Sv3) connected to a speaker (HP3) to inform the user of the nature of the event that triggered an alarm. and / or to help with programming. 7. System according to claim 6, characterized in that the speech synthesis circuit (Sv3) is connected to a telephone control circuit (C3) to automatically dial at least one telephone number and inform a specific subscriber of the occurrence and   the nature of an event at the user of the system.   8. System according to claim 6, characterized in that the speech synthesis circuit (Sv3) is connected to a high frequency transmitter (HF3) for transmitting messages towards at least   a receiver (RF3) located in the perimeter to be monitored.   9. System according to any one of claims 3 to 6,   characterized in that the central unit has display means   display (V3) and / or a printer (Im3) to inform the user of events occurring in the perimeter to be monitored and / or help with programming   10. System according to claim 3, characterized in that the   display means (V3) consist of alphanumeric displays.   digital and / or different LEDs.   He. System according to one of Claims 3 to 10,   characterized in that it comprises at least one device (Ptl, Pt2) to remotely arm or disarm all or part of the detectors, in that the gatekeeper comprises a keyboard (T) for dialing a code transmitted to the receiver (R3 ) of the central unit and   analyzed by the processing unit (Tr3).   12. System according to claim 1 1, characterized in that the gatekeeper makes it possible to remotely control at least one connected detector to an automatism.   13. System according to one of claims 1i1 or 12, characterized   in that the gatekeeper (Pt1, Pt2) is fixed.   14. System according to claim 13, characterized in that the fixed gatekeeper allows the control of a visitor bell.   15. System according to one of claims 11 or 12, characterized   in that the gatekeeper (Pt1, Pt2) is mobile.   16. System according to one of the preceding claims, characterized   characterized in that the transmission of the signals between the transmitters (T1) and the central unit (CPU) is carried out by radio and in that the means of identification of a transmitter consist of two parts, a first (I1) to distinguish it from other transmitters in communication with the same central unit, and a second (G 1) to distinguish it from another transmitter in communication with another central unit, the first of which part (I1) would be identical.   17. System according to claim 16, characterized in that the transmitter further comprises a battery (B1) for its power supply, a microprocessor (MP1) whose output is connected to a transmitter (E1) for transmitting towards the unit Central (UC), and in   an input (21) of the microprocessor (MP1) is connected to a detection   specialized detector (D1) for detecting a given event, and in that the detection of an event results in the transmission of a coded signal from the transmitter (E1) and produced by the microprocessor, this   signal containing information relating to the identity of the trans-   director and information about the event, so that the unit   central unit activates the alarm corresponding to the associated detector.   18. System according to claim 17, characterized in that the transmitter (T1) is in the form of a housing in which the elements are enclosed, and in that a detector (D1l) contained in said housing is activated when of its opening, so that a code containing information on the opening and the identity of the transmitter is transmitted to the central unit, so that a alarm is triggered.   19. System according to one of claims 17 or 18, characterized   in that each transmission towards the central unit is memorized by the microprocessor (MP) and that when the   number of transmissions from a transmitter (T1) reaches a prede-   completed, an encoded signal containing information relating to the identity of the transmitter and to said number of transmissions is transmitted in direction of the central unit.   20. System according to one of claims 17 or 18, characterized   in that each transmitter (T1) comprises means for measuring the energy remaining in the battery (B1), and means for transmitting a coded signal towards the central unit (uc)   when the residual energy is less than a given value.   21. System according to any one of the preceding claims   characterized in that each transmitter comprises means for periodically transmitting a message informing the unit central to his presence.   22. System according to claim 21, characterized in that   Presence message is issued every two hours or so.   23. System according to any one of claims 3 to 22,   characterized in that the central unit (CU) is supplied by the electrical network (EL) from the locations where it is located and in that it comprises a transmitter (E3) arranged to transmit coded signals on the network, when an alarm must be triggered, and in that the alarm receivers (RA1 ... RAn) are directly connected to the   network and controlled by signals transmitted over the network.   24. System according to claims 4 and 23, characterized in that   that the signals transmitted on the network (EL) by the central unit   information about the identity of the alarm receiver   (RA1, ... RAn) associated with the device to be triggered.   25. System according to any one of claims 3 to 24,   characterized in that the programming keyboard (PR3) of the central unit (CPU) makes it possible to associate at least one transmitter (T1 ... Tn) with at least one alarm receiver (RA1 ... RAn) and / or the speech synthesis circuit (Sv3)