Manual of U.S. Patent Classification
as of June 30, 2000

Class
340
COMMUNICATIONS: ELECTRICAL

Class definitions may be accessed by clicking on the class title, above.
Subclass definitions may be accessed by clicking on the subclass number, below.

Patents classified in a subclass may be accessed by clicking on the " " icon following the subclass number, below.

( please note that links to definitions and classified patents may not be available for some classes and subclasses )

For search strategies, please refer to the Classification Index Explanation of Data web page.

Subclass		Title
ClassTitle		===> COMMUNICATIONS: ELECTRICAL
850		UNDERWATER
851		. Ship guidance system
852		. Electrodes and electrode systems
853.1		WELLBORE TELEMETERING OR CONTROL (E.G., SUBSURFACE TOOL GUIDANCE, DATA TRANSFER, ETC.)
853.2		. Diagnostic monitoring or detecting operation of communications equipment or signal
853.3		. Selective control of subsurface equipment
853.4		. . In horizontal or inclined drilling or passage
853.5		. . . Control of drilling apparatus using magnetic field
853.6		. . Control of drill bit or apparatus (e.g., steering, speed, etc.)
853.7		. Repeater in subsurface link (e.g., cable, etc.)
853.8		. With orientation sensing of subsurface telemetering equipment (other than drilling equipment)
853.9		. Including detail of subsurface signal storage (e.g., memory, recorder, register, etc.)
854.1		. With position or depth recording (e.g., line payout, equipment locator, etc.)
854.2		. . Location of collar or stuck tool
854.3		. Using a specific transmission medium (e.g., conductive fluid, annular spacing, etc.)
854.4		. . Drill string or tubing support signal conduction
854.5		. . Wellbore casing or ground
854.6		. . Electromagnetic energy (e.g., radio frequency, etc.)
854.7		. . . Optical link (e.g., waveguide, etc.)
854.8		. . . Near field coupling (e.g., inductive, capacitive, etc.)
854.9		. . Cable or wire (e.g., conductor as support, etc.)
855.1		. . . Coupling connection structural feature
855.2		. . . Single conductor cable or wire
855.3		. Multiplexed signals
855.4		. Pulse or digital signal transmission
855.5		. . Digital signal processing in subsurface transmitter
855.6		. . . Having acoustic sensor
855.7		. Modification of signal bandwidth, frequency, or circuit impedance at subsurface location
855.8		. Including specified power transmission feature or source (e.g., battery, etc.)
855.9		. . Specified alternating current (A.C.) circuit feature
856.1		. In horizontal or inclined passage arrangement
856.2		. With expandable or inflatable sensor element or mounting
856.3		. Including particular sensor
856.4		. . Acoustic or vibratory (e.g., sonic, fluidic, etc.)
870.01		CONTINUOUSLY VARIABLE INDICATING (E.G., TELEMETERING)
870.02		. With meter reading
870.03		. . Having plural transmitters
870.04		. With calibration
870.05		. With calculation
870.06		. . Plural transmitters (e.g., ratio)
870.07		. Combined (TM system with other system)
870.08		. . Radio dial
870.09		. . With alarm or annunciator (concurrent with TM)
870.1		. For radio sonde
870.11		. Plural transmitters
870.12		. . Frequency division multiplex
870.13		. . Time division multiplex
870.14		. . . Using particular sync
870.15		. . With plural receiver
870.16		. Condition responsive
870.17		. . Temperature
870.18		. Using a particular modulation (e.g., phase, frequency, or amplitude)
870.19		. . Pulse
870.2		. . . Pulse repetition
870.21		. . . Analog to digital function converter
870.22		. . . Permutation code
870.23		. . . Increase pulses plus decrease pulses
870.24		. . . Pulse duration (e.g., pulse train)
870.25		. Phase variation
870.26		. Frequency variation
870.27		. Plural circuits, each for particular magnitude
870.28		. Via radiant energy beam (via particular energy)
870.29		. . Photoelectric cell pickup
870.3		. With particular transmitter (e.g., piezoelectric, dynamo)
870.31		. . Inductive transmitter
870.32		. . . Mutual inductance
870.33		. . . . Flux valve type (e.g., with movable saturating magnet)
870.34		. . . . Self-synchronous type
870.35		. . . . Differential type
870.36		. . . . . Linear variable differential transformer (LVDT)
870.37		. . Capacitive transmitter
870.38		. . Resistive transmitter
870.39		. With supply voltage regulation or compensation
870.4		. With particular receiver (e.g., ratiometer)
870.41		. . Plural receivers
870.42		. . With feedback (e.g., reflex along line)
870.43		. . . Follow-up (e.g., circuit rebalanced when upset)
870.44		. . With discharge device (e.g., CRT)
901		EXTERNAL CONDITION VEHICLE-MOUNTED INDICATOR OR ALARM
902		. Transmitter in another vehicle (e.g., emergency vehicle)
903		. . Relative distence between vehicles (e.g., collision alert)
904		. Transmitter in one vehicle only
905		. Highway information (e.g., weather, speed limits, etc.)
906		OVERRIDE OF TRAFFIC CONTROL INDICATOR BY COMMAND TRANSMITTER
907		TRAFFIC CONTROL INDICATOR
908		. Portable
908.1		. . Barricade marker
909		. Plural intersections under common central station control
910		. . Central station responsive to traffic detectors
911		. . . Central station controls offset (time between beginning of same phase at adjacent intersections)
912		. . Standby cycling implemented if invalid transmission received or loss of transmission occurs
913		. . Offset control
914		. . Split control
915		. . Central station includes display of status of indicators
916		. Intersection normally under local controller
917		. . Controller responsive to traffic detectors
918		. . . Controller, when changing right of way, alters or skips normal "go" cycle of street having no traffic detected
919		. . . Plural cross highways at intersection each have traffic detectors
920		. . . . Density determines split
921		. . . . . Extension of time
922		. . . Density determines split
923		. . . Extension of time
924		. . Local controller can be superceded by central station controller
925		. . Pedestrian control
926		. . Manual setting of cycle length and split times
927		. . Rotating cam structure (specific structure required)
928		. Combined (e.g., toll systems, one-way)
929		. Indication of time remaining before change of phase
930		. . Electromechanical movable auxiliary indicator
931		. Traffic control or local controller failure indicator
932		. Pacing (e.g., vehicle keeps pace with sequentially activated lights)
932.1		. Pivoted
932.2		VEHICLE PARKING INDICATORS
933		VEHICLE DETECTORS
934		. Density
935		. Discriminates vehicle direction
936		. Speed and overspeed
937		. With camera
938		. Compensation for vehicle remaining at sensor position
939		. Environmental or drift compensation
940		. With pneumatic
941		. Inductive
942		. Photoelectric
943		. Sonic or ultrasonic
944		PEDESTRIAN GUIDANCE
945		AIRCRAFT ALARM OR INDICATING SYSTEMS
946		. Nonairplane (e.g., balloon or helicopter)
947		. Land-based landing guidance
948		. . Aircraft actuation of land-based landing guides
949		. . Wind direction
950		. . Movable (e.g., rotatable) guides
951		. . Phased landing guidance (e.g., runway approach, landing, touchdown)
952		. . Particular energy guide source (e.g., sound, electric field, radio)
953		. . . Visual source
954		. . . . Alignment of plural sources
955		. . . . Plural colors
956		. . . . Modulated light source
957		. . . Magnetic field guide
958		. Docking guidance
959		. Takeoff indicator
960		. Landing gear indicator
961		. Potential collision with other aircraft
962		. Icing indicator
963		. Flight alarm
964		. . Phased warnings for same flight condition
965		. . Tactile
966		. . Stall
967		. . Attitude (including yaw, angle of attack, roll, pitch, glide slope)
968		. . Wind shear
969		. . Speed
970		. . Altitude
971		. Nonalarm flight indicator
972		. . Runway presentation
973		. . Indicator of at least four flight parameters (altitude, speed, etc.)
974		. . Attitude
975		. . . Roll or pitch
976		. . . Glide slope or path
977		. . Altitude
978		. . Speed
979		. . Heading (includes deviation from desired course)
980		. . Indicator visible in pilot's line of sight through windscreen
981		. Aircraft beacons
982		. . Lights communicate (e.g., direction, altitude, reference position to observer)
983		. Obstruction beacon
984		WATERCRAFT ALARM OR INDICATING SYSTEMS
985		. Navigation guides (e.g., channel lights)
986		. Anchor movement
987		. Rudder position indicator
988		VEHICLE POSITION INDICATION
989		. At remote location
990		. . With map display
991		. . Position indication transmitted by vehicle after receipt of information from local station
992		. . Position indication transmitted at periodic intervals (e.g., distance travelled)
993		. . Position indication transmitted by local station to remote location
994		. . Vehicle's arrival or expected arrival at remote location along route indicated at that remote location (e.g., bus arrival systems)
995		. Map display
996		. Prerecorded message describes position
425.5		LAND VEHICLE ALARMS OR INDICATORS
426		. Of burglary or unauthorized use
427		. . Of motorcycles or bicycles
428		. . Responsive to changes in voltage or current in a vehicle electrical system
429		. . Responsive to inertia, vibration, or tilt
430		. . With entrance/exit time delay
431		. For trailer
432		. For bicycle
433		. For school bus
434		. For taxi
435		. Of relative distance from an obstacle
436		. Of collision or contact with external object
437		. . Curb
438		. Internal alarm or indicator responsive to a condition of the vehicle
439		. . Operation efficiency (e.g., engine performance, driver habits)
440		. . Tilt, imbalance, or overload
441		. . Speed of vehicle, engine, or power train
442		. . Tire deflation or inflation
443		. . . By indirect detection means (e.g., height measurement)
444		. . . . Relative wheel speed
445		. . . With particular telemetric coupling
446		. . . . Acoustic wave
447		. . . . Radio wave
448		. . . . Inductive
449		. . Temperature
450		. . Fluid level
450.1		. . . Of hydraulic brake fluid
450.2		. . . Of fuel
450.3		. . . Of lubricant (e.g., engine oil)
451		. . Fluid pressure
452		. . . Of brake fluid
453		. . Brake or clutch condition
454		. . . Wear
455		. . Battery charging system condition
456		. . Gear position
457		. . Reminder
457.1		. . . Of seat belt application
457.2		. . . Of headlight energization
457.3		. . . Of parking brake application
457.4		. . . Of service interval expiration
458		. . Lamp or lamp circuit condition
459		. . Plural conditions
460		. . . With voice warning
461		. . . With particular display means
462		. . . . Digital
463		. External alarm or indicator of movement
464		. . Plural indications (e.g., go, slow, stop)
465		. . Turning or steering
466		. . Speed
467		. . Acceleration or deceleration
468		. External signal light system
469		. . With two or more intensity levels (e.g., day or night)
470		. . Pass - no pass
471		. . Hazard warning or distress signalling
472		. . . Auxiliary signal permanently attached to vehicle
473		. . . Portable signal
474		. . With audible signal
475		. . Turn signal
476		. . . With automatic cancelling
477		. . . . By predetermined time interval or distance
478		. . . With plural bulbs sequentially flashed
479		. . Brake light
480		. Electromagnetically actuated mechanical signal
481		. . Wigwag type
482		. . Normally encased
483		. . . Plural concurrent indicators
484		. . . Sliding sign or shutter
485		. . . Window exhibited sign or shutter
486		. . . . Drum
487		. . Pivoting
488		. . . Multiple indicators
489		. . . Three or more positions
490		. . . . Vertical axis
146.2		DIGITAL COMPARATOR SYSTEMS
500		CONDITION RESPONSIVE INDICATING SYSTEM
501		. With particular system function (e.g., temperature compensation, calibration)
502		. . Acknowledgement
503		. . . With ringback
504		. . Answer-back
505		. . Interrogator-responder
506		. . Alarm system supervision
507		. . . Fail-safe
508		. . . Redundant (e.g., added circuit or loop)
509		. . . Plural or diverse current sources
510		. . . Bridge or potential divider
511		. . . Threshold or window (e.g., of analog electrical level)
512		. . . Pulse
513		. . . Diode
514		. . Testing
515		. . . Simulation of condition
516		. . . Automatic (e.g., periodic, start-up)
517		. . Selection from a plurality of sensed conditions
518		. . . Scanning
519		. . . Worst condition
520		. . . First sensed exclusively indicated
521		. . . Plural diverse conditions
522		. . . . Combined for response
523		. . . Particular sequence of conditions
524		. . . Condition position indicator
525		. . . . Display board
526		. . Predetermined rate of occurrence
527		. . Time delay
528		. . . Entrance/exit
529		. . . Condition persistence
530		. . . . Capacitor
531		. With particular coupling link
532		. . Having particular safety function
533		. . Wired
534		. . . Coded message
535		. . . . Mechanical code means (e.g., coded disc)
536		. . . Noninterfering
537		. . . With impedance level coding
538		. . . Combined with power line
539		. . Radio
540		. Specific condition
541		. . Intrusion detection
542		. . . Lock
543		. . . . Permutation
544		. . . Disturbance of fluid pressure
545.1		. . . Door or window movement
546		. . . . Portable
545.2		. . . . Specified sensor
547		. . . . . Magnetic sensor
548		. . . . . Plug or cord tension sensor
549		. . . . . Rotatable sensor
545.3		. . . . . Sensing of electromagnetic energy (e.g., light, infrared, or microwave)
545.4		. . . . . Sensing of electrical parameter (e.g., piezoelectricity or capacitance)
545.5		. . . . . Inertia-type sensor (e.g., mercury or pendulum switch)
545.6		. . . . Door, cover, or lid for self-contained article (e.g., refrigerator, mailbox, drawer, cabinet, or box)
545.7		. . . . Specified door or window portion (e.g., doorknob)
545.8		. . . . Specified door or window attachment (e.g., shade or blind)
545.9		. . . . Plural doors or windows
550		. . . Partition penetration
551		. . . Disturbance of magnetic field
552		. . . Disturbance of electromagnetic waves
553		. . . . Standing waves
554		. . . . Doppler effect
555		. . . . Light
556		. . . . . Beam
557		. . . . . . Laser
561		. . . Disturbance of electric field
562		. . . . Capacitance
563		. . . . . With bridge
564		. . . . . Fence
565		. . . Responsive to intruder energy
566		. . . . Vibration
567		. . . . Electromagnetic energy
568.1		. . Article placement or removal (e.g., anti-theft)
568.2		. . . Signal-carrying conduit between sensor and article (e.g., cable, power cord, or data link)
568.3		. . . . Power cord
568.4		. . . . Specified connector (e.g., phone jack-type plug)
568.5		. . . Shopping cart or item thereon
568.6		. . . Sporting equipment (e.g., golfbag, club, cart, or skis)
568.7		. . . Currency, credit card, or container therefor (e.g., wallet or handbag)
568.8		. . . Article on pedestal, in display case, or mounted on wall (e.g., work of art)