G08BSIGNALLING OR CALLING SYSTEMSORDER TELEGRAPHSALARM SYSTEMSThis subclass covers also means for identifying or incapacitating burglars or the like.This subclass does not cover: the mere provision of an audible or visible signalling device on measuring or switching apparatus; alarm systems for indicating that a specific variable has exceeded, or fallen below, a predetermined value, which are covered by the relevant subclasses of class G01 for the measurement of that variable.alarms for specific processes or types of machines or apparatus, which are covered by the relevant subclasses for the processes, machines, or apparatus.In this subclass, the following term is used with the meaning indicated: "systems" may cover also devices peculiar thereto. In this subclass non-limiting references (in the sense of paragraph 39 of the Guide to the IPC) may still be displayed in the scheme. G08B1/00 G08B1/00Systems for signalling characterised solely by the form of transmission of the signal G08B1/02using only mechanical transmission G08B1/04using hydraulic transmissionusing pneumatic transmission G08B1/06hydraulic only G08B1/08using electric transmission ; transformation of alarm signals to electrical signals from a different medium, e.g. transmission of an electric alarm signal upon detection of an audible alarm signal G08B2001/085Partner search devices G08B3/00Audible signalling systemsAudible personal calling systems G08B3/02using only mechanical transmission G08B3/06using hydraulic transmissionusing pneumatic transmission G08B3/10using electric transmissionusing electromagnetic transmission G08B3/1008Personal calling arrangements or devices, i.e. paging systems selective calling systems and call receivers H04W84/00, H04W68/00 G08B3/1016using wireless transmission calling systems using transmission by inductive loop H04B5/04 G08B3/1025Paging receivers with audible signalling details G08B3/1033with voice message alert G08B3/1041with alternative alert, e.g. remote or silent alert G08B3/105with call or message storage means G08B3/1058Pager holders or housings casings for electric apparatus H05K5/00 G08B3/1066with other provisions not elsewhere provided for, e.g. turn-off protection G08B3/1075Paging racks G08B3/1083Pager locating systems G08B3/1091Group calling G08B3/14using explosives G08B5/00Visible signalling systems, e.g. personal calling systems, remote indication of seats occupied G08B5/002Distress signalling devices, e.g. rescue balloons vehicle optical signalling for indicating emergencies B60Q1/52 G08B5/004Reflective safety signalling devices attached on persons G08B5/006Portable traffic signalling devices G08B5/004 takes precedence; emergency signalling devices to be placed on roads or vehicles B60Q7/00 G08B5/008Traffic signalling mirrors G08B5/02using only mechanical transmission G08B5/06using hydraulic transmissionusing pneumatic transmission G08B5/14with indicator element moving about a pivot, e.g. hinged flap or rotating vane G08B5/16with reset means necessitating a separate operation to return the indicator element G08B5/18with indicator element moving rectilinearly G08B5/20with reset means necessitating a separate operation to return the indicator element G08B5/22using electric transmissionusing electromagnetic transmission G08B5/221Local indication of seats occupied in a facility, e.g. in a theatre G08B5/222Personal calling arrangements or devices, i.e. paging systems selective calling systems and call receivers H04W84/00, H04W68/00 G08B5/223using wireless transmission G08B5/224Paging receivers with visible signalling details G08B5/225Display details G08B5/226with alphanumeric or graphic display means G08B5/227with call or message storage means G08B5/228combined with other devices having a different main function, e.g. watches G08B5/229with other provisions not elsewhere provided for G08B5/24with indicator element moving about a pivot, e.g. hinged flap or rotating vane G08B5/26with reset means necessitating a separate operation to return the indicator element G08B5/28with hinged flap or arm G08B5/30with rotating or oscillating members, e.g. vanes G08B5/32with indicator element moving rectilinearly G08B5/34with reset means necessitating a separate operation to return the indicator element G08B5/36using visible light sources G08B5/38using flashing light G08B5/40using smoke, fire or coloured gases G08B6/00Tactile signalling systems, e.g. personal calling systems G08B7/00Signalling systems according to more than one of groups G08B3/00 - G08B6/00Personal calling systems according to more than one of groups G08B3/00 - G08B6/00 G08B7/02using mechanical transmission G08B7/04using hydraulic transmissionusing pneumatic transmission G08B7/06using electric transmission , e.g. involving audible and visible signalling through the use of sound and light sources G08B7/062indicating emergency exits G08B7/064indicating houses needing emergency help, e.g. with a flashing light or sound G08B7/066guiding along a path, e.g. evacuation path lighting strip G08B7/068calling personnel in a restaurant, e.g. waiter call G08B7/08using explosives G08B9/00Order telegraph apparatus, i.e. means for transmitting one of a finite number of different orders at the discretion of the user, e.g. bridge to engine room orders in ships G08B9/02Details G08B9/04Means for recording operation of the apparatus G08B9/06Means for indicating disagreement between orders given and those carried out G08B9/08mechanical G08B9/10using ratchet G08B9/12using rotary shaft G08B9/14hydraulicpneumatic G08B9/16using ratchet G08B9/18by varying displacement of the fluid G08B9/20by varying pressure of the fluid G08B13/00Burglar, theft or intruder alarms G08B13/02Mechanical actuation G08B13/04by breaking of glass G08B13/06by tampering with fastening G08B13/08by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind G08B13/10by pressure on floors, floor coverings, stair treads, counters, or tills G08B13/12by the breaking or disturbance of stretched cords or wires G08B13/122for a perimeter fence features peculiar to electrified fences A01K3/00 G08B13/124with the breaking or disturbance being optically detected, e.g. optical fibers in the perimeter fence G08B13/126for a housing, e.g. a box, a safe, or a room G08B13/128the housing being an electronic circuit unit, e.g. memory or CPU chip protecting computer components in secure or tamper resistant housings G06F21/86; protecting computer input devices, e.g. keyboards G06F21/83 G08B13/14by lifting or attempted removal of hand-portable articles G08B13/1409for removal detection of electrical appliances by detecting their physical disconnection from an electrical system, e.g. using a switch incorporated in the plug connector G08B13/1418Removal detected by failure in electrical connection between the appliance and a control centre, home control panel or a power supply G08B13/1427with transmitter-receiver for distance detection Details thereof are further classified in the subgroups of G08B21/0202 G08B13/1436with motion detection G08B13/1445with detection of interference with a cable tethering an article, e.g. alarm activated by detecting detachment of article, breaking or stretching of cable furniture, e.g. shelves for displaying merchandise, incorporating tethers to prevent theft A47F7/024, A47F5/0861 G08B13/1454Circuit arrangements thereof G08B13/1463Physical arrangements, e.g. housings devices to prevent theft or loss of purses, luggage or hand carried bags A45C13/18 G08B13/1472with force or weight detection G08B13/1481with optical detection G08B13/149with electric, magnetic, capacitive switch actuation G08B13/16Actuation by interference with mechanical vibrations in air or other fluid G08B13/1609using active vibration detection systems G08B13/1618using ultrasonic detection means G08B13/1627using Doppler shift detection circuits G08B13/1636using pulse-type detection circuits G08B13/1645using ultrasonic detection means and other detection means, e.g. microwave or infra-red radiation G08B13/1654using passive vibration detection systems G08B13/1663using seismic sensing means G08B13/1672using sonic detecting means, e.g. a microphone operating in the audio frequency range G08B13/1681using infrasonic detecting means, e.g. a microphone operating below the audible frequency range G08B13/169using cable transducer means G08B13/18Actuation by interference with heat, light, or radiation of shorter wavelengthActuation by intruding sources of heat, light, or radiation of shorter wavelength G08B13/181using active radiation detection systems G08B13/183by interruption of a radiation beam or barrier G08B13/184using radiation reflectors G08B13/186using light guides, e.g. optical fibres G08B13/187by interference of a radiation field G08B13/189using passive radiation detection systems G08B13/1895using light change detection systems G08B13/194 takes precedence G08B13/19using infra-red-radiation detection systems G08B13/194 takes precedence G08B13/191using pyroelectric sensor means G08B13/193using focusing means G08B13/194using image scanning and comparing systems G08B13/196using television cameras G08B13/19602Image analysis to detect motion of the intruder, e.g. by frame subtraction G08B13/19604involving reference image or background adaptation with time to compensate for changing conditions, e.g. reference image update on detection of light level change G08B13/19606Discriminating between target movement or movement in an area of interest and other non-signicative movements, e.g. target movements induced by camera shake or movements of pets, falling leaves, rotating fan G08B13/19608Tracking movement of a target, e.g. by detecting an object predefined as a target, using target direction and or velocity to predict its new position G08B13/1961Movement detection not involving frame subtraction, e.g. motion detection on the basis of luminance changes in the image G08B13/19613Recognition of a predetermined image pattern or behaviour pattern indicating theft or intrusion G08B13/19615wherein said pattern is defined by the user G08B13/19617Surveillance camera constructional details G08B13/19619Details of casing G08B13/19621Portable camera G08B13/19623Arrangements allowing camera linear motion, e.g. camera moving along a rail cable or track G08B13/19626optical details, e.g. lenses, mirrors or multiple lenses G08B13/19628of wide angled cameras and camera groups, e.g. omni-directional cameras, fish eye, single units having multiple cameras achieving a wide angle view G08B13/1963Arrangements allowing camera rotation to change view, e.g. pivoting camera, pan-tilt and zoom [PTZ] G08B13/19632Camera support structures, e.g. attachment means, poles G08B13/19634Electrical details of the system, e.g. component blocks for carrying out specific functions G08B13/19636pertaining to the camera G08B13/19639Details of the system layout G08B13/19641Multiple cameras having overlapping views on a single scene G08B13/19643wherein the cameras play different roles, e.g. different resolution, different camera type, master-slave camera G08B13/19645Multiple cameras, each having view on one of a plurality of scenes, e.g. multiple cameras for multi-room surveillance or for tracking an object by view hand-over G08B13/19647Systems specially adapted for intrusion detection in or around a vehicle G08B13/1965the vehicle being an aircraft G08B13/19652Systems using zones in a single scene defined for different treatment, e.g. outer zone gives pre-alarm, inner zone gives alarm G08B13/19654Details concerning communication with a camera G08B13/19656Network used to communicate with a camera, e.g. WAN, LAN, Internet G08B13/19658Telephone systems used to communicate with a camera, e.g. PSTN, GSM, POTS G08B13/1966Wireless systems, other than telephone systems, used to communicate with a camera G08B13/19663Surveillance related processing done local to the camera G08B13/19665Details related to the storage of video surveillance data television signal recording H04N5/76 G08B13/19667Details realated to data compression, encryption or encoding, e.g. resolution modes for reducing data volume to lower transmission bandwidth or memory requirements G08B13/19669Event triggers storage or change of storage policy G08B13/19671Addition of non-video data, i.e. metadata, to video stream G08B13/19673Addition of time stamp, i.e. time metadata, to video stream G08B13/19676Temporary storage, e.g. cyclic memory, buffer storage on pre-alarm G08B13/19678User interface G08B13/1968Interfaces for setting up or customising the system G08B13/19682Graphic User Interface [GUI] presenting system data to the user, e.g. information on a screen helping a user interacting with an alarm system G08B13/19684Portable terminal, e.g. mobile phone, used for viewing video remotely G08B13/19686Interfaces masking personal details for privacy, e.g. blurring faces, vehicle license plates G08B13/19689Remote control of cameras, e.g. remote orientation or image zooming control for a PTZ camera G08B13/19691Signalling events for better perception by user, e.g. indicating alarms by making display brighter, adding text, creating a sound G08B13/19693using multiple video sources viewed on a single or compound screen G08B13/19695Arrangements wherein non-video detectors start video recording or forwarding but do not generate an alarm themselves G08B13/19697Arrangements wherein non-video detectors generate an alarm themselves G08B13/20Actuation by change of fluid pressure G08B13/22Electrical actuation G08B13/24by interference with electromagnetic field distribution G08B13/2402Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting mechanical aspects of the tags, e.g. related to locking E05B73/0017; RFID readers G06K7/00; RFID tags G06K19/00; access control systems G07C9/00; anti-theft control in point of sale systems G07G3/003; security seals G09F3/03 G08B13/2405characterised by the tag technology used G08B13/2408using ferromagnetic tags G08B13/2411Tag deactivation G08B13/2414using inductive tags G08B13/2417having a radio frequency identification chip G08B13/242Tag deactivation G08B13/2422using acoustic or microwave tags G08B13/2425Tag deactivation G08B13/2428Tag details G08B13/2431Tag circuit details G08B13/2434Tag housing and attachment details G08B13/2437Tag layered structure, processes for making layered tags G08B13/244Tag manufacturing, e.g. continuous manufacturing processes G08B13/2442Tag materials and material properties thereof, e.g. magnetic material details G08B13/2445Tag integrated into item to be protected, e.g. source tagging G08B13/2448Tag with at least dual detection means, e.g. combined inductive and ferromagnetic tags, dual frequencies within a single technology, tampering detection or signalling means on the tag G08B13/2451Specific applications combined with EAS G08B13/2454Checking of authorisation of a person accessing tagged items in an EAS system G08B13/2457Lending systems using EAS tags wherein the tags are reusable, e.g. they can be activated and deactivated more than once, e.g. for a library G08B13/246Check out systems combined with EAS, e.g. price information stored on EAS tag anti-theft systems in point of sale systems G07G3/003 G08B13/2462Asset location systems combined with EAS inventory, tracking, logistic G06Q10/00; entrance control systems G07C9/00 G08B13/2465Aspects related to the EAS system, e.g. system components other than tags G08B13/2468Antenna in system and the related signal processing G08B13/2471Antenna signal processing by receiver or emitter G08B13/2474Antenna or antenna activator geometry, arrangement or layout loop antennae H01Q1/22 G08B13/2477Antenna or antenna activator circuit G08B13/248EAS system combined with another detection technology, e.g. dual EAS and video or other presence detection system G08B13/2482EAS methods, e.g. description of flow chart of the detection procedure G08B13/2485Simultaneous detection of multiple EAS tags G08B13/2488Timing issues, e.g. synchronising measures to avoid signal collision, with multiple emitters or a single emitter and receiver G08B13/2491Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field G08B13/2494by interference with electro-magnetic field distribution combined with other electrical sensor means, e.g. microwave detectors combined with other sensor means G08B13/2497using transmission lines, e.g. cable G08B13/26by proximity of an intruder causing variation in capacitance or inductance of a circuit G08B15/00Identifying, scaring or incapacitating burglars, thieves or intruders, e.g. by explosives G08B15/001Concealed systems, e.g. disguised alarm systems to make covert systems G08B15/002with occupancy simulation G08B15/004using portable personal devices hand-held or body-worn self-defence devices using repellent gases or chemicals F41H9/10 G08B15/005by electric shock G08B15/007by trapping G08B15/008by simulating the existence of a security system, e.g. a mock video camera to scare thieves G08B15/02with smoke, gas, or coloured or odorous powder or liquid G08B17/00Fire alarmsAlarms responsive to explosion G08B17/005for forest fires, e.g. detecting fires spread over a large or outdoors area fire fighting forest fires A62C3/02 G08B17/02Mechanical actuation of the alarm, e.g. by the breaking of a wire G08B17/04Hydraulic or pneumatic actuation of the alarm, e.g. by change of fluid pressure G08B17/06Electric actuation of the alarm, e.g. using a thermally-operated switch G08B17/08Actuation involving the use of explosive means G08B17/10Actuation by presence of smoke or gases , e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means G08B17/103using a light emitting and receiving device G08B17/107for detecting light-scattering due to smoke G08B17/11using an ionisation chamber for detecting smoke or gas G08B17/113Constructional details G08B17/117by using a detection device for specific gases, e.g. combustion products, produced by the fire G08B17/103, G08B17/11 take precedence G08B17/12Actuation by presence of radiation or particles, e.g. of infra-red radiation or of ions G08B17/125by using a video camera to detect fire or smoke G08B19/00Alarms responsive to two or more different undesired or abnormal conditions, e.g. burglary and fire, abnormal temperature and abnormal rate of flow G08B19/005combined burglary and fire alarm systems G08B19/02Alarm responsive to formation or anticipated formation of ice G08B21/00Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for G08B21/02Alarms for ensuring the safety of persons G08B21/0202Child monitoring systems using a transmitter-receiver system carried by the parent and the child G08B21/0205Specific application combined with child monitoring using a transmitter-receiver system G08B21/0208Combination with audio or video communication, e.g. combination with "baby phone" function G08B21/0211Combination with medical sensor, e.g. for measuring heart rate, temperature G08B21/0213System disabling if a separation threshold is exceeded disabling electrical appliances in case of unplugging G08B13/1409 G08B21/0216Alarm cancellation after generation G08B21/0219Circuit arrangements G08B21/0222Message structure or message content, e.g. message protocol G08B21/0225Monitoring making use of different thresholds, e.g. for different alarm levels G08B21/0227System arrangements with a plurality of child units G08B21/023Power management, e.g. system sleep and wake up provisions G08B21/0233System arrangements with pre-alarms, e.g. when a first distance is exceeded G08B21/0236Threshold setting G08B21/0238adding new units to the system G08B21/0241Data exchange details, e.g. data protocol G08B21/0244System arrangements wherein the alarm criteria uses signal delay or phase shift G08B21/0247System arrangements wherein the alarm criteria uses signal strength G08B21/025System arrangements wherein the alarm criteria uses absence of reply signal after an elapsed time G08B21/0252System arrangements wherein the child unit emits, i.e. the child unit incorporates the emitter G08B21/0255System arrangements wherein the parent unit emits, i.e. the parent unit incorporates the emitter G08B21/0258System arrangements wherein both parent and child units can emit and receive G08B21/0261System arrangements wherein the object is to detect trespassing over a fixed physical boundary, e.g. the end of a garden G08B21/0263System arrangements wherein the object is to detect the direction in which child or item is located G08B21/0266System arrangements wherein the object is to detect the exact distance between parent and child or surveyor and item G08B21/0269System arrangements wherein the object is to detect the exact location of child or item using a navigation satellite system, e.g. GPS G08B21/0272System arrangements wherein the object is to detect exact location of child or item using triangulation other than GPS G08B21/0275Electronic Article Surveillance [EAS] tag technology used for parent or child unit, e.g. same transmission technology, magnetic tag, RF tag, RFID G08B21/0277Communication between units on a local network, e.g. Bluetooth, piconet, zigbee, Wireless Personal Area Networks [WPAN] G08B21/028Communication between parent and child units via remote transmission means, e.g. satellite network G08B21/0283via a telephone network, e.g. cellular GSM G08B21/0286Tampering or removal detection of the child unit from child or article G08B21/0288Attachment of child unit to child/article G08B21/0291Housing and user interface of child unit G08B21/0294Display details on parent unit G08B21/0297Robbery alarms, e.g. hold-up alarms, bag snatching alarms G08B21/04responsive to non-activity, e.g. of elderly persons G08B21/06 takes precedence G08B21/0407based on behaviour analysis G08B21/0415detecting absence of activity per se G08B21/0423detecting deviation from an expected pattern of behaviour or schedule G08B21/043detecting an emergency event, e.g. a fall G08B21/0438Sensor means for detecting G08B21/0446worn on the body to detect changes of posture, e.g. a fall, inclination, acceleration, gait G08B21/0453worn on the body to detect health condition by physiological monitoring, e.g. electrocardiogram, temperature, breathing detecting, measuring or recording for diagnostic purposes A61B5/00 G08B21/0461integrated or attached to an item closely associated with the person but not worn by the person, e.g. chair, walking stick, bed sensor G08B21/0469Presence detectors to detect unsafe condition, e.g. infrared sensor, microphone G08B21/0476 takes precedence G08B21/0476Cameras to detect unsafe condition, e.g. video cameras G08B21/0484Arrangements monitoring consumption of a utility or use of an appliance which consumes a utility to detect unsafe condition, e.g. metering of water, gas or electricity, use of taps, toilet flush, gas stove or electric kettle G08B21/0492Sensor dual technology, i.e. two or more technologies collaborate to extract unsafe condition, e.g. video tracking and RFID tracking G08B21/06indicating a condition of sleep, e.g. anti-dozing alarms G08B21/08responsive to the presence of persons in a body of water, e.g. a swimming poolresponsive to an abnormal condition of a body of water G08B21/082by monitoring electrical characteristics of the water G08B21/084by monitoring physical movement characteristics of the water G08B21/086by monitoring a perimeter outside the body of the water G08B21/088by monitoring a device worn by the person, e.g. a bracelet attached to the swimmer G08B21/10responsive to calamitous events, e.g. tornados or earthquakes G08B21/12responsive to undesired emission of substances, e.g. pollution alarms G08B21/14Toxic gas alarms G08B21/16 takes precedence G08B21/16Combustible gas alarms G08B21/18Status alarms G08B21/02 takes precedence G08B21/182Level alarms, e.g. alarms responsive to variables exceeding a threshold G08B21/185Electrical failure alarms G08B21/187Machine fault alarms G08B21/20responsive to moisture G08B21/22responsive to presence or absence of persons G08B21/24Reminder alarms, e.g. anti-loss alarms G08B21/245Reminder of hygiene compliance policies, e.g. of washing hands G08B23/00Alarms responsive to unspecified undesired or abnormal conditions G08B25/00Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems G08B25/001Alarm cancelling procedures or alarm forwarding decisions, e.g. based on absence of alarm confirmation G08B25/002Generating a prealarm to the central station G08B25/003Address allocation methods and details G08B25/004Alarm propagated along alternative communication path or using alternative communication medium according to a hierarchy of available ways to communicate, e.g. if Wi-Fi not available use GSM G08B25/005Alarm destination chosen according to a hierarchy of available destinations, e.g. if hospital does not answer send to police station G08B25/006Alarm destination chosen according to type of event, e.g. in case of fire phone the fire service, in case of medical emergency phone the ambulance G08B25/007Details of data content structure of message packets; data protocols G08B25/008Alarm setting and unsetting, i.e. arming or disarming of the security system G08B25/009Signalling of the alarm condition to a substation whose identity is signalled to a central station, e.g. relaying alarm signals in order to extend communication range G08B25/01characterised by the transmission medium G08B25/012using recorded signals, e.g. speech G08B25/08 takes precedence G08B25/014Alarm signalling to a central station with two-way communication, e.g. with signalling back G08B25/016Personal emergency signalling and security systems emergency non-personal manually actuated alarm activators G08B25/12 G08B25/018Sensor coding by detecting magnitude of an electrical parameter, e.g. resistance G08B25/04using a single signalling line, e.g. in a closed loop G08B25/045with sensing devices and central station in a closed loop, e.g. McCullough loop G08B25/06using power transmission lines G08B25/08using communication transmission lines G08B13/19658, G08B21/0286, G08B25/016 take precedence G08B25/085using central distribution transmission lines G08B25/10using wireless transmission systems G08B25/009 takes precedence G08B25/12Manually actuated calamity alarm transmitting arrangements emergency non-personal manually actuated alarm, activators, e.g. details of alarm push buttons mounted on an infrastructure G08B25/14Central alarm receiver or annunciator arrangements G08B26/00Alarm systems in which substations are interrogated in succession by a central station G08B26/001with individual interrogation of substations connected in parallel G08B26/002only replying the state of the sensor G08B26/003replying the identity and the state of the sensor G08B26/004with common interrogation of substations G08B26/005with substations connected in series, e.g. cascade G08B26/006with substations connected to an individual line, e.g. star configuration G08B26/007Wireless interrogation G08B26/008central annunciator means of the sensed conditions, e.g. displaying or registering G08B27/00Alarm systems in which the alarm condition is signalled from a central station to a plurality of substations G08B27/001Signalling to an emergency team, e.g. firemen G08B27/003Signalling to neighbouring houses G08B27/005with transmission via computer network G08B27/006with transmission via telephone network G08B27/008with transmission via TV or radio broadcast G08B29/00Checking or monitoring of signalling or alarm systemsPrevention or correction of operating errors, e.g. preventing unauthorised operation G08B29/02Monitoring continuously signalling or alarm systems G08B29/04Monitoring of the detection circuits G08B29/043of fire detection circuits G08B29/046prevention of tampering with detection circuits G08B29/06Monitoring of the line circuits, e.g. signalling of line faults G08B29/08Signalling of tampering with the line circuit G08B29/10Monitoring of the annunciator circuits G08B29/12Checking intermittently signalling or alarm systems G08B29/123of line circuits G08B29/126of annunciator circuits G08B29/14checking the detection circuits G08B29/145of fire detection circuits G08B29/16Security signalling or alarm systems, e.g. redundant systems G08B29/18Prevention or correction of operating errors G08B29/02, G08B29/12 take precedence G08B29/181due to failing power supply G08B29/183Single detectors using dual technologies G08B13/1672, G08B13/2448, G08B13/2494 take precedence G08B29/185Signal analysis techniques for reducing or preventing false alarms or for enhancing the reliability of the system G08B29/186Fuzzy logic; neural networks G08B29/188Data fusion; cooperative systems, e.g. voting among different detectors G08B29/20Calibration, including self-calibrating arrangements G08B29/22Provisions facilitating manual calibration, e.g. input or output provisions for testingHolding of intermittent values to permit measurement G08B29/24Self-calibration, e.g. compensating for environmental drift or ageing of components G08B29/26by updating and storing reference thresholds G08B29/28by changing the gain of an amplifier G08B31/00Predictive alarm systems characterised by extrapolation or other computation using updated historic data