|  | G |
SECTION G — PHYSICS

|  | G |
Note(s) In this section, the following term is used with the meaning indicated: "variable" (as a noun) means a feature or property (e.g., a dimension, a physical condition such as temperature, a quality such as density or colour) which, in respect of a particular entity (e.g., an object, a quantity of a substance, a beam of light) and at a particular instant, is capable of being measured; the variable may change, so that its numerical expression may assume different values at different times, in different conditions or in individual cases, but may be constant in respect of a particular entity in certain conditions or for practical purposes (e.g., the length of a bar may be regarded as constant for many purposes). Attention is drawn to the definitions of terms or expressions used, appearing in the notes of several of the classes in this section, in particular those of "measuring" in class Fulltext... Hierarchy... Expanded...G01 and "control" and "regulation" in class Fulltext... Hierarchy... Expanded...G05. Classification in this section may present more difficulty than in other sections, because the distinction between different fields of use rests to a considerable extent on differences in the intention of the user rather than on any constructional differences or differences in the manner of use, and because the subjects dealt with are often in effect systems or combinations, which have features or parts in common, rather than "things", which are readily distinguishable as a whole. For example, information (e.g., a set of figures) may be displayed for the purpose of education or advertising (Fulltext... Hierarchy... Expanded...G09), for enabling the result of a measurement to be known (Fulltext... Hierarchy... Expanded...G01), for signalling the information to a distant point or for giving information which has been signalled from a distant point (Fulltext... Hierarchy... Expanded...G08). The words used to describe the purpose depend on features that may be irrelevant to the form of the apparatus concerned, for example, such features as the desired effect on the person who sees the display, or whether the display is controlled from a remote point. Again, a device which responds to some change in a condition, e.g., in the pressure of a fluid, may be used, without modification of the device itself, to give information about the pressure (Fulltext... Hierarchy... Expanded...G01L) or about some other condition linked to the pressure (another subclass of class Fulltext... Hierarchy... Expanded...G01, e.g., Fulltext... Hierarchy... Expanded...G01K for temperature), to make a record of the pressure or of its occurrence (Fulltext... Hierarchy... Expanded...G07C), to give an alarm (Fulltext... Hierarchy... Expanded...G08B), or to control another apparatus (Fulltext... Hierarchy... Expanded...G05). The classification scheme is intended to enable things of a similar nature (as indicated above) to be classified together. It is therefore particularly necessary for the real nature of any technical subject to be decided before it can be properly classified.

INSTRUMENTS

|  | G08 |
SIGNALLING (indicating or display devices per se Fulltext... Hierarchy... Expanded...G09F; transmission of pictures Fulltext... Hierarchy... Expanded...H04N)

|  | G08B |
SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS (signalling arrangements on vehicles Fulltext... Hierarchy... Expanded...B60Q, Fulltext... Hierarchy... Expanded...B62D 41/00; railway signalling systems or devices Fulltext... Hierarchy... Expanded...B61L; on cycles Fulltext... Hierarchy... Expanded...B62J 3/00, Fulltext... Hierarchy... Expanded...B62J 6/00; safes or strong-rooms with alarm devices Fulltext... Hierarchy... Expanded...E05G; signalling or alarm devices in mines Fulltext... Hierarchy... Expanded...E21F 17/18; lamps or shutters therefor Fulltext... Hierarchy... Expanded...F21; sensitive measuring elements, see the appropriate subclasses of Fulltext... Hierarchy... Expanded...G01; traffic control systems Fulltext... Hierarchy... Expanded...G08G; visual indicating means Fulltext... Hierarchy... Expanded...G09; sound-producing devices Fulltext... Hierarchy... Expanded...G10; radio or near-field calling systems Fulltext... Hierarchy... Expanded...H04B 5/00, Fulltext... Hierarchy... Expanded...H04B 7/00; selecting arrangements Fulltext... Hierarchy... Expanded...H04Q 7/00, Fulltext... Hierarchy... Expanded...H04Q 9/00; loudspeakers, microphones, gramohpone pick-ups or like acoustic electromechanical transducers Fulltext... Hierarchy... Expanded...H04R)

|  | G08B |
Note(s) This 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 Fulltext... Hierarchy... Expanded...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.

|  | G08B |
Subclass index
SIGNALLING OR CALLING SYSTEMS |
Characterised by the transmission of the signal | 1/00
Characterised by the nature of the indication: audible; visible; tactile; combined | 3/00; 5/00; 6/00; 7/00
ORDER TELEGRAPHS | 9/00
ALARM SYSTEMS |
Responsive to an unspecified condition | 23/00
Responsive to two or more different conditions | 19/00
Responsive to one specified condition: intrusion; fire; other | 13/00, 15/00; 17/00; 21/00
With transmission from or to a central station | 25/00, 26/00, 27/00
Predictive alarm systems | 31/00
CHECKING, MONITORING | 29/00

|  | G08B 1/00 |
Systems for signalling characterised solely by the form of transmission of the signal

|  | G08B 1/02 |
· | using only mechanical transmission

|  | G08B 1/04 |
· | using hydraulic transmission; using pneumatic transmission

|  | G08B 1/06 |
· · | hydraulic only

|  | G08B 1/08 |
· | using electric transmission

|  | G08B 3/00 |
Audible signalling systems; Audible personal calling systems (audible indication of time signals Fulltext... Hierarchy... Expanded...G04B 21/00, Fulltext... Hierarchy... Expanded...G04C 21/00)

|  | G08B 3/02 |
· | using only mechanical transmission

|  | G08B 3/06 |
· | using hydraulic transmission; using pneumatic transmission

|  | G08B 3/10 |
· | using electric transmission; using electromagnetic transmission

|  | G08B 3/14 |
· | using explosives

|  | G08B 5/00 |
Visible signalling systems, e.g. personal calling systems, remote indication of seats occupied (display of time signals Fulltext... Hierarchy... Expanded...G04B 19/00, Fulltext... Hierarchy... Expanded...G04C 17/00, Fulltext... Hierarchy... Expanded...G04C 19/00, Fulltext... Hierarchy... Expanded...G04G 9/00; for display of alphanumeric information Fulltext... Hierarchy... Expanded...G09F; flags, banners Fulltext... Hierarchy... Expanded...G09F)

|  | G08B 5/02 |
· | using only mechanical transmission

|  | G08B 5/06 |
· | using hydraulic transmission; using pneumatic transmission

|  | G08B 5/14 |
· · | with indicator element moving about a pivot, e.g. hinged flap, rotating vane

|  | G08B 5/16 |
· · · | with reset means necessitating a separate operation to return the indicator element

|  | G08B 5/18 |
· · | with indicator element moving rectilinearly

|  | G08B 5/20 |
· · · | with reset means necessitating a separate operation to return the indicator element

|  | G08B 5/22 |
· | using electric transmission; using electromagnetic transmission

|  | G08B 5/24 |
· · | with indicator element moving about a pivot, e.g. hinged flap, rotating vane

|  | G08B 5/26 |
· · · | with reset means necessitating a separate operation to return the indicator element

|  | G08B 5/28 |
· · · | with hinged flap or arm

|  | G08B 5/30 |
· · · | with rotating or oscillating members, e.g. vanes

|  | G08B 5/32 |
· · | with indicator element moving rectilinearly

|  | G08B 5/34 |
· · · | with reset means necessitating a separate operation to return the indicator element

|  | G08B 5/36 |
· · | using visible light sources

|  | G08B 5/38 |
· · · | using flashing light

|  | G08B 5/40 |
· | using smoke, fire, or coloured gases (sky-writing Fulltext... Hierarchy... Expanded...G09F 21/16)

|  | G08B 6/00 |
Tactile signalling systems, e.g. personal calling systems (indication of time by feeling Fulltext... Hierarchy... Expanded...G04B 25/02; deaf-aid sets Fulltext... Hierarchy... Expanded...H04R 25/00) [6]

|  | G08B 7/00 |
Signalling systems according to more than one of groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G08B 3/00-G08B 6/00 (combinations of display arrangements with audible advertising Fulltext... Hierarchy... Expanded...G09F 27/00); Personal calling systems according to more than one of groups Fulltext... Hierarchy... Expanded...Fulltext... Hierarchy... Expanded...G08B 3/00-G08B 6/00

|  | G08B 7/02 |
· | using mechanical transmission

|  | G08B 7/04 |
· | using hydraulic transmission; using pneumatic transmission

|  | G08B 7/06 |
· | using electric transmission

|  | G08B 7/08 |
· | using explosives

|  | G08B 9/00 |
Order 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 (signalling devices in mines Fulltext... Hierarchy... Expanded...E21F 17/18)

|  | G08B 9/02 |
· | Details

|  | G08B 9/04 |
· · | Means for recording operation of the apparatus

|  | G08B 9/06 |
· · | Means for indicating disagreement between orders given and those carried out

|  | G08B 9/08 |
· | mechanical

|  | G08B 9/10 |
· · | using ratchet

|  | G08B 9/12 |
· · | using rotary shaft

|  | G08B 9/14 |
· | hydraulic; pneumatic

|  | G08B 9/16 |
· · | using ratchet

|  | G08B 9/18 |
· · | by varying displacement of the fluid

|  | G08B 9/20 |
· · | by varying pressure of the fluid

|  | G08B 13/00 |
Burglar, theft, or intruder alarms (vehicle theft alarms Fulltext... Hierarchy... Expanded...B60R 25/10; cycle theft alarms Fulltext... Hierarchy... Expanded...B62H 5/00)

|  | G08B 13/02 |
· | Mechanical actuation

|  | G08B 13/04 |
· · | by breaking of glass

|  | G08B 13/06 |
· · | by tampering with fastening (alarm locks Fulltext... Hierarchy... Expanded...E05B 45/00; alarm devices on safes Fulltext... Hierarchy... Expanded...E05G 1/10)

|  | G08B 13/08 |
· · | by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind

|  | G08B 13/10 |
· · | by pressure on floors, floor coverings, stair treads, counters, or tills

|  | G08B 13/12 |
· · | by the breaking or disturbance of stretched cords or wires

|  | G08B 13/14 |
· · | by lifting or attempted removal of hand-portable articles

|  | G08B 13/16 |
· | Actuation by interference with mechanical vibrations in air or other fluid

|  | G08B 13/18 |
· | Actuation by interference with heat, light, or radiation of shorter wavelength; Actuation by intruding sources of heat, light, or radiation of shorter wavelength

|  | G08B 13/181 |
· · | using active radiation detection systems [5]

|  | G08B 13/183 |
· · · | by interruption of a radiation beam or barrier (light barriers Fulltext... Hierarchy... Expanded...G01V 8/10) [5]

|  | G08B 13/184 |
· · · · | using radiation reflectors [5]

|  | G08B 13/186 |
· · · · | using light guides, e.g. optical fibres [5]

|  | G08B 13/187 |
· · · | by interference of a radiation field [5]

|  | G08B 13/189 |
· · | using passive radiation detection systems [5]

|  | G08B 13/19 |
· · · | using infra-red-radiation detection systems [5]

|  | G08B 13/191 |
· · · · | using pyroelectric sensor means [5]

|  | G08B 13/193 |
· · · · | using focusing means [5]

|  | G08B 13/194 |
· · · | using image scanning and comparing systems [5]

|  | G08B 13/196 |
· · · · | using television cameras [5]

|  | G08B 13/20 |
· | Actuation by change of fluid pressure

|  | G08B 13/22 |
· | Electrical actuation

|  | G08B 13/24 |
· · | by interference with electromagnetic field distribution

|  | G08B 13/26 |
· · | by proximity of an intruder causing variation in capacitance or inductance of a circuit

|  | G08B 15/00 |
Identifying, scaring, or incapacitating burglars, thieves, or intruders, e.g. by explosives (burglar traps, or the like, on safes Fulltext... Hierarchy... Expanded...E05G 5/02)

|  | G08B 15/02 |
· | with smoke, gas, or coloured or odorous powder or liquid

|  | G08B 17/00 |
Fire alarms; Alarms responsive to explosion (temperature-responsive elements Fulltext... Hierarchy... Expanded...G01K)

|  | G08B 17/02 |
· | Mechanical actuation of the alarm, e.g. by the breaking of a wire

|  | G08B 17/04 |
· | Hydraulic or pneumatic actuation of the alarm, e.g. by change of fluid pressure

|  | G08B 17/06 |
· | Electric actuation of the alarm, e.g. using a thermally-operated switch (thermally-operated electric switches per se Fulltext... Hierarchy... Expanded...H01H 37/00)

|  | G08B 17/08 |
· | Actuation involving the use of explosive means

|  | G08B 17/10 |
· | Actuation by presence of smoke or gases

|  | G08B 17/103 |
· · | using a light emitting and receiving device [5]

|  | G08B 17/107 |
· · · | for detecting light-scattering due to smoke [5]

|  | G08B 17/11 |
· · | using an ionisation chamber for detecting smoke or gas (vacuum gauges making use of ionisation effects Fulltext... Hierarchy... Expanded...G01L 21/30; gas analysis by investigating the ionisation Fulltext... Hierarchy... Expanded...G01N 27/62) [5]

|  | G08B 17/113 |
· · · | Constructional details (discharge tubes for measuring pressure of introduced gas, or for detecting presence of gas, in general Fulltext... Hierarchy... Expanded...H01J 41/02) [5]

|  | G08B 17/117 |
· · | by using a detection device for specific gases, e.g. combustion products, produced by the fire (Fulltext... Hierarchy... Expanded...G08B 17/103, Fulltext... Hierarchy... Expanded...G08B 17/11 take precedence; investigating or analysing gases in general Fulltext... Hierarchy... Expanded...G01N, e.g. by using electric means Fulltext... Hierarchy... Expanded...G01N 27/00) [5]

|  | G08B 17/12 |
· | Actuation by presence of radiation or particles, e.g. of infra-red radiation, of ions

|  | G08B 19/00 |
Alarms responsive to two or more different undesired or abnormal conditions, e.g. burglary and fire, abnormal temperature and abnormal rate of flow

|  | G08B 19/02 |
· | Alarm responsive to formation or anticipated formation of ice (indicating weather conditions Fulltext... Hierarchy... Expanded...G01W 1/00)

|  | G08B 21/00 |
Alarms responsive to a single specified undesired or abnormal operating condition and not elsewhere provided for

|  | G08B 23/00 |
Alarms responsive to unspecified undesired or abnormal conditions

|  | G08B 25/00 |
Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems

|  | G08B 25/01 |
· | characterised by the transmission medium [5]

|  | G08B 25/04 |
· · | using a single signalling line, e.g. in a closed loop [5]

|  | G08B 25/06 |
· · | using power transmission lines (systems in general for transmission of information via power distribution lines Fulltext... Hierarchy... Expanded...H04B 3/54) [5]

|  | G08B 25/08 |
· · | using communication transmission lines (telephonic communication systems combined with alarm systems Fulltext... Hierarchy... Expanded...H04M 11/04) [5]

|  | G08B 25/10 |
· · | using wireless transmission systems [5]

|  | G08B 25/12 |
· | Manually actuated calamity alarm transmitting arrangements [5]

|  | G08B 25/14 |
· | Central alarm receiver or annunciator arrangements [5]

|  | G08B 26/00 |
Alarm systems in which substations are interrogated in succession by a central station

|  | G08B 27/00 |
Alarm systems in which the alarm condition is signalled from a central station to a plurality of substations

|  | G08B 29/00 |
Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation

|  | G08B 29/02 |
· | Monitoring continuously signalling or alarm systems [5]

|  | G08B 29/04 |
· · | Monitoring of the detection circuits [5]

|  | G08B 29/06 |
· · | Monitoring of the line circuits, e.g. signalling of line faults (testing or locating faults in cables or lines in general Fulltext... Hierarchy... Expanded...G01R 31/02, Fulltext... Hierarchy... Expanded...G01R 31/08) [5]

|  | G08B 29/08 |
· · · | Signalling of tampering with the line circuit [5]

|  | G08B 29/10 |
· · | Monitoring of the annunciator circuits [5]

|  | G08B 29/12 |
· | Checking intermittently signalling or alarm systems [5]

|  | G08B 29/14 |
· · | checking the detection circuits [5]

|  | G08B 29/16 |
· | Security signalling or alarm systems, e.g. redundant systems [5]

|  | G08B 29/18 |
· | Prevention or correction of operating errors (Fulltext... Hierarchy... Expanded...G08B 29/02, Fulltext... Hierarchy... Expanded...G08B 29/12 take precedence) [5]

|  | G08B 29/20 |
· · | Calibration, including self-calibrating arrangements [5]

|  | G08B 29/22 |
· · · | Provisions facilitating manual calibration, e.g. input or output provisions for testing; Holding of intermittent values to permit measurement [5]

|  | G08B 29/24 |
· · · | Self-calibration, e.g. compensating for environmental drift or ageing of components [5]

|  | G08B 29/26 |
· · · · | by updating and storing reference thresholds [5]

|  | G08B 29/28 |
· · · · | by changing the gain of an amplifier [5]

|  | G08B 31/00 |
Predictive alarm systems characterised by extrapolation or other computation using updated historic data [5]