PATENTS   
Patents > Guidance, Tools, and Manuals >> Classification >>> Class Definition
    Class Numbers & Titles   | Class Numbers Only   | USPC Index   | International   | HELP  
You are viewing a Class definition.

 [Search a list of Patent Appplications for class 340]   CLASS 340,COMMUNICATIONS: ELECTRICAL
Click here for a printable version of this file

SECTION I - CLASS DEFINITION

This is the residual home for subject matter, not elsewhere classified, relating to communication by means which are in part or in whole electrical.

Communications is defined, for the purpose of this definition, as being the handling of information or intelligence and is not restricted to the conveying of said information or intelligence between geographically spaced points. (Thus, a traffic obstruction light which merely marks a safety island is a means for communicating information or intelligence, viz., the fact of the presence of the traffic island).

Information or intelligence is defined, for the purpose of this definition, as being the subject matter which is handled by signaling systems or signaling devices (such as telegraph systems) or by that portion of nonsignaling systems or nonsignaling devices (such as power supply systems) which is designated in the arts as having a control function (such as the supervisory circuits which control the circuit breakers of an electric power network).

Handling, as used above, is defined as being the active coaction between the tangible communication system or device and the intangible information or intelligence, and such coaction may assume various forms, such as transmission, storage, exhibiting, etc.

(1) Note. Since Class 340 takes, under the class definition, only those electrical communication systems which are not elsewhere classified, the search, in order to be complete, must, in appropriate instances, extend elsewhere. See Lines With Other Classes, below.
(2) Note. The combination of the subject matter of this class (340) and art environment is generally classified with the art environment where that environment is significant, either by virtue of a significant disclosed relationship or by virtue of a claimed relationship. Where the art environment is recited by name only, the combination may be classified, in some instances, with the art environment, and in others, in this class (340). For a list of some of the other classes which contain pertinent subject matter, see the classes referred to under SEARCH CLASS.
(3) Note. This classification was produced in 1952 by making official the unofficial digests which had been established by the Examiners of Division 42 during the period from about 1910 to about 1942. A caveat is given: While it is believed that the titles and definitions are reasonably correct, no assurance can be given that all of the patents, issued prior to the date of reclassification, are in the proper subclass, since the individual patents were not read during the reclassification project. Consequently, in making a thorough search in this class, it is advisable to investigate every subclass which may possibly be pertinent and not, in order to shorten the search, to rely on the principle of superiority of subclass subject matter because of position in schedule, since the principle is applicable only in classes where each patent has been analyzed and placed in the schedule in accordance with that portion of the disclosed subject matter which is claimed.

SECTION II - LINES WITH OTHER CLASSES AND WITHIN THIS CLASS

Since Class 340 takes, under the class definition, only those electrical communication systems which are not elsewhere classified, the search, in order to be complete, must, in appropriate instances, extend to Class 178, Class 246, Class 250, Class 332, Class 343, Class 346, Class 348, and Class 379. See References to Other Classes, below.

LINE BETWEEN CLASSES 116, 250, 340, AND 343

Class 250, Radiant Energy, for signaling systems of the radiant energy type. Such signaling systems are coextensively classified in Class 343, and the class definitions of these two classes should be consulted for the line between Classes 250 and 343, and the class definition of Class 343 for the line between Classes 343 and 116. Note that Class 340 provides for telemetering along a radiant energy beam and for signaling systems having a radiant energy responsive detector.

LINE BETWEEN CLASSES 342, 250, 340, AND 343

Class 342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation) appropriate subclasses for signaling systems of the radio wave energy type. See the reference to Class 250, supra, for the lines between Classes 250, 340, and 343. See Class 343 for antennas with a signal, indicator, or alarm which is responsive to the scan, sweep, or orientation of the antenna; and for antennas with a signal, indicator, or alarm responsive to some other condition of the antenna. See subclass 700 of Class 343 for certain classification lines involving antennas and signals, indicators, and alarms.

SECTION III - SUBCLASS REFERENCES TO THE CURRENT CLASS

SEE OR SEARCH THIS CLASS, SUBCLASS:

901,through 996, The following conventions will apply to the definition of these subclasses: (a) A signal is an information-carrying wave; (b) A indicator is a device which makes information concerning a condition available. (c) An alarm is an indicator which makes information available only upon the occurrence of a preselected state of the condition.
289,320, for a significantly recited electric signaling system.
533,538, 288, and 310.11 for the combination of a Class 340 system and a Class 178 system.

SECTION IV - REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:

15, Brushing, Scrubbing, and General Cleaning,   subclass 339 for brushing, scrubbing and general cleaning machines having a signal or indicator to indicate the condition of the machine or work.
34, Drying and Gas or Vapor Contact With Solids,   subclass 89 for apparatus of that class combined with indicating or signaling means.
40, Card, Picture, or Sign Exhibiting,   subclasses 463+ for electrically actuated changeable exhibitors, such as the advertising display type and subclasses 541+ for illuminated signs having significant sign structure in addition to electric illumination. Advertising display elements arranged in matrix are in class (345) subclasses 55+.
43, Fishing, Trapping, and Vermin Destroying,   subclass 16 , 17, and 58 for the subject matter of that class combined with signals and indicators.
70, Locks,   subclass 434 for locks combined with electric recorders for indicating the previous condition of the lock, and other appropriate subclasses for locks combined with electric signals.
73, Measuring and Testing,   appropriate subclasses for testing devices which make a test of the Class 73 type (usually nonelectrical and nonchemical) and signal the result of said test by electrical means. Note particularly subclasses 23.2+ , 301, 304, 308, 313, 717+, 723+, 733+, and 753+.
81, Tools,   subclass 479 for torque-responsive wrenches or screwdrivers having electrical means to indicate when a selected torque is exerted.
84, Music,   subclass 405 for xylophones with electric action, subclass 407 for bell sets (carillons) with electric action and subclass 462 for electric devices responsive to playing of a musical instrument for recording the action of said instrument.
99, Foods and Beverages: Apparatus,   subclass 285 for beverage infusers having signal means and subclasses 342+ for cookers having signal means.
100, Presses,   subclass 99 for presses having electrical means to indicate the condition of the press or the material being pressed.
109, Safes, Bank Protection, or a Related Device,   subclasses 38+ for safes and analogous structures having alarm devices for signaling loss of integrity.
114, Ships,   subclass 246 for indicators for locating the position of a towed vessel with respect to the towing vessel.
116, Signals and Indicators, see Lines With Other Classes and Within This Class,   in the class definition for the line between the electrical signals in Class 340 and the mechanical signals in Class 116. Search appropriate subclasses of Class 116 for mechanical signals and indicators analogous to the electrical signals and indicators of Class 340. Search subclass 20 for helios:graphic signaling along a light ray.
118, Coating Apparatus,   subclasses 712+ for coating apparatus having a signal or indicator.
119, Animal Husbandry,   subclasses 14.14+ for milkers having a signal or indicator.
134, Cleaning and Liquid Contact With Solids,   subclass 113 for cleaning or wetting devices having signals or indicators.
137, Fluid Handling,   subclasses 551+ for fluid handling equipment having signal or indicating means.
160, Flexible or Portable Closure, Partition, or Panel,   subclass 10 for the subject matter of that class having signals or indicators.
169, Fire Extinguishers,   subclasses 19+ for fire extinguishing systems having automatically opened valves and subclass 23 for fire extinguishing systems having alarms which indicate some abnormal condition of the fire extinguishing system. The nominal combination of a fire extinguishing system, recited nonsignificantly, as by name only, and a significantly recited electric signaling system is classified in appropriate subclasses of Class 340, (for which see Subclass References to the Current Class above)
174, Electricity: Conductors and Insulators,   subclass 11 for fluid-insulated conductors having means to indicate the condition of the fluid.
177, Weighing Scales,   subclasses 45+ for a weigher having an alarm or signal.
178, Telegraphy,   appropriate subclasses for telegraphic signaling. See the class definition of Class 178 for the line between Classes 178 and 340. The combination of a Class 340 system and a Class 178 system is classified in Class 340 in appropriate subclasses, see Subclass References to the Current Class above.
181, Acoustics,   subclasses 101+ for mechanical compressional wave devices and systems, such as those used in seismic prospecting, subclasses 123+, for mechanical sound echo systems, and subclass 125 for mechanical sound location apparatus and methods.
182, Fire Escape, Ladder, or Scaffold,   subclass 18 for a fire escape, ladder, or scaffold having an indicator, signal or alarm.
185, Motors: Spring, Weight, or Animal Powered,   subclass 14 , 36, and 44 for spring and weight motors having indicators to show the extent to which they are wound up or run down.
187, Elevator, Industrial Lift Truck, or Stationary Lift for Vehicle,   appropriate subclasses for signalling means in combination or limited to use with elevator structure.
188, Brakes,   appropriate subclasses for significantly claimed brakes or brake systems combined with signals.
194, Check-Actuated Control Mechanisms,   subclasses 302+ for coin controlled mechanisms having a signal to indicate the condition (e.g., counterfeit coin) of the mechanism.
198, Conveyors: Power-Driven,   subclass 40 for conveyors having signaling means.
200, Electricity: Circuit Makers and Breakers,   subclass 308 for switches having indicators to indicate the position or condition of the switch.
215, Bottles and Jars,   subclasses 365+ for receptacles having indicating means and subclasses 201+, 227, and 230 for closures having indicating means.
219, Electric Heating,   subclass 109 for a current supply indicator (e.g., a recorder, etc.) to a metal heating (e.g., resistance heating, etc.) pressure bonding (e.g., resistance welding, etc.) apparatus, subclass 209 combined with a diverse-type electrical art device, subclass 248 for a heating device combined with a sole plate-type pressure application means (e.g., a flatiron, etc.) including a condition-responsive indicator, subclass 269 for an igniter-type resistive element indicating means, subclass 445.1 for an exposed planar support surface for material to be heated (e.g., hot plate, etc.) including an indicator, subclasses 446.1+ for an exposed planar support surface for material to be heated (e.g., hot plate, etc.) including a sensing means, subclass 487 for a heating device having a power supply and voltage or current regulation or current control means to control or regulate plural separate distinct heating resistance elements (i.e., one control system for all elements, etc.) selectively, sequentially, or alternately including indicator means, subclass 506 for a heating device having automatic regulating or control of power supply and voltage including signal or indicator means, subclass 667 for a condition responsive temperature load sensing power switching supply system for an inductive heating device, subclass 714 for a remote control system for a microwave heating device, subclass 719 for a timer control system for a microwave heating device, or subclass 720 where a control system for a microwave heating device has a display or alarm.
221, Article Dispensing,   subclasses 2+ for article dispensers not otherwise classified having indicators or signals.
222, Dispensing,   subclasses 23+ for fluent material dispensing means having indicators or signals.
232, Deposit and Collection Receptacles,   subclasses 34 through 37for letter boxes having signals or indicators.
234, Selective Cutting (e.g., Punching),   subclasses 4+ for a typographical punching machine provided with means to indicate approach to and entry into the justification zone; subclasses 13+ and 22+, for a selective cutting machine with automatic control usually initiated by an indicator or detector of a given operating condition; subclasses 59+, for a pattern-controlled selective cutting machine which may be electrically operated.
235, Registers,   subclass 61 for mechanical calculators, subclasses 400+ for ordnance control data calculators, subclasses 419+ for electromechanical or mechanical record controlled calculators, subclasses 435+ for coded record sensors, and subclasses 487+ for coded records adapted to be read by machine.
241, Solid Material Comminution or Disintegration,   subclass 101.01 for the subject matter of that class having signals and indicators.
242, Winding, Tensioning, or Guiding,   subclass 357 , 472.0+, 479.9+, 484.8, 484.9+, 534+, 563+, and 912 for a detector, signal, or indicator associated with winding or unwinding an elongated material.
246, Railway Switches and Signals,   for railway signaling and control systems. See the class definition of Class 246 for the line between Classes 246 and 340.
250, Radiant Energy,   for signaling systems of the radiant energy type; subclasses 306+ for methods and apparatus for inspecting solids or liquids by charged particles, subclasses 330+ for the detection of infrared patterns and the conversion of the pattern into a light image, subclasses 336.1+ for methods and apparatus to detect and indicate the intensity or frequency of invisible radiation or the testing of materials by detecting and indicating the change in invisible radiation caused by the material, and subclasses 200 to 239 for photocell light-responsive circuits and apparatus. (See Lines With Other Classes and Within This Class)
258, Railway Mail Delivery,   subclass 2 for the subject matter of that class (which includes delivery to and from airborne vehicles) having signaling features.
276, Typesetting,   subclass 11 for typesetting machines having means for indicating the length of the line set.
291, Track Sanders,   subclass 17 for track and vehicle sanding machines provided with alarms to indicate the operation thereof.
307, Electrical Transmission or Interconnection Systems,   appropriate subclasses for the subject matter of that class having signals and indicators. Note that many of the systems of this class, while not having signals and indicators, have automatic controls which are analogous to signals.
312, Supports: Cabinet Structure,   subclasses 234+ for cabinets having indicators.
313, Electric Lamp and Discharge Devices,   subclass 10 for electric space discharge devices, such as vacuum tubes, or electric lamps having temperature indicators.
314, Electric Lamp and Discharge Devices: Consumable Electrodes,   subclass 9 for electric arc lamps having a signal or indicator.
315, Electric Lamp and Discharge Devices: Systems,   subclasses 129+ for electric gas discharge device systems or electric lamp systems having signals, indicators or alarms and subclasses 364+ for space discharge devices testing or lamp testing equipment having signals or indicators.
318, Electricity: Motive Power Systems,   subclass 490 for electric motor systems having signals or indicators.
320, Electricity: Battery or Capacitor Charging or Discharging,   appropriate subclass for a battery or capacitor charging or discharging circuit combined with an indicator.
322, Electricity: Single Generator Systems,   subclass 99 for electric generator systems having signals or indicators.
324, Electricity: Measuring and Testing,   appropriate subclasses for testing systems for making tests of electric properties having means to indicate the result of the test. Note subclasses 323+ for testing systems for locating ore bodies having means to indicate the result of the test, and subclasses 76.11+ for meters for measuring a property of an electric current or voltage or combination thereof (e.g., power factor, watt-hours, phase angle frequency). Telemetering systems which utilize a meter as a portion thereof are in Class 340 subclasses 870.02+, but the meter subcombination, per se, is classified with the meters of Class 324. Telemetering systems which, by significantly claimed structure or circuit, indicate the result of an electrical test at a point remote from the point of measurement are classified with the test in Class 324, as such telemetering systems are not of general utility, but are restricted to use in Class 324 measurements.
329, Demodulators,   for demodulators of modulated intelligence including continuous waves (CW), and which furnish something more than the mere indication of the initiation of the signal.
331, Oscillators,   appropriate subclasses, for electric oscillation generators of utility in the communication systems of Class 340. Class 331, subclass 64 for oscillator systems provided with an indicator, signal or alarm.
332, Modulators,   subclass 118 and 150 for modulators having signals and indicators.
333, Wave Transmission Lines and Networks,   for wave transmission systems wherein electromagnetic wave energy is guided or constrained by a propagation medium of appreciable electrical length as compared to the wavelength of the propagated energy. This class includes numerous networks and components useful in communications. Note particularly subclass 20 for wave-shaping networks of the passive type, subclasses 24+ for coupling networks including delay networks and filters, and subclasses 236+ for long lines having distributed electrical parameters, and subclasses 1+ for plural channel systems of these lines and networks.
336, Inductor Devices,   subclass 45 for inductors having movable parts and means to indicate the position of the movable part.
338, Electrical Resistors,   subclasses 13+ and 68+ for variable resistors including rheostats and potentiometers.
341, Coded Data Generation or Conversion,   appropriate subclasses for code conversion, transmission or generation.
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar,   Radio Navigation) appropriate subclasses for signaling systems of the radio wave energy type. (See Lines With This Class and Within Other Classes.)
345, Computer Graphics Processing and Selective Visual Display Systems,   subclasses 1.1 through 3.4for plural display systems, and subclasses 418-475 for computer graphics processing.
346, Recorders,   appropriate subclasses for signals or indicators which record, and subclass 16 and 17+ for recorders combined with signals and indicators.
348, Television,   appropriate subclasses for television communication systems.
356, Optics: Measuring and Testing,   for visible light type testing and examination instruments particularly for light radar devices in subclasses 3+ , subclasses 43+ for optical pyrometers, subclass 625 for measuring dimension, subclass 388 for configuration comparison devices, subclass 402 for shade or color test devices, subclasses 213+ for photometers, and subclasses 237.1+ for flaw and imperfection devices.
358, Facsimile and Static Presentation Processing,   appropriate subclasses for data processing for static presentation to printer, and facsimile communication systems.
360, Dynamic Magnetic Information Storage or Retrieval,   appropriate subclass for read/write dynamic storage systems.
362, Illumination,   appropriate subclasses for illuminating means which may serve as signalling means.
365, Static Information Storage and Retrieval,   appropriate subclass for read/write static storage systems, subclasses 185.01+ for floating gate memory storage (e.g., flash memory).
367, Communications, Electrical: Acoustic Wave Systems and Devices,   for electrical communication systems in which the intelligence communicated is transmitted in part as acoustic wave energy.
368, Horology: Time Measuring Systems or Devices,   subclasses 46+ for electric systems which indicate time and for electric clocks.
370, Multiplex Communications,   appropriate subclasses for multiplexing systems.
374, Thermal Measuring and Testing,   subclasses 163+ for a thermometer with an electrical heat sensor and a quantitative signalling arrangement.
377, Electrical Pulse Counters, Pulse Dividers, or Shift Registers: Circuits and Systems,   subclasses 112+ for electrical counters with display or indication.
380, Cryptography,   subclasses 255 through 276for a communication system using cryptography.
381, Electrical Audio Signal Processing and Systems,   appropriate subclasses for one-way audio signal transmission and audio signal processing systems.
396, Photography,   subclasses 429+ for a camera combined with diverse art devices.
400, Typewriting Machines,   appropriate subclasses for typewriters having signals to indicate the condition or operation of the machine. Note particularly subclasses 70+ .
404, Road Structure, Process, or Apparatus,   subclasses 9+ for nonelectric roadway structure designed to direct traffic.
406, Conveyors: Fluid Current,   subclasses 34+ for conveyors having signals or indicators.
422, Chemical Apparatus and Process Disinfecting, Deodorizing, Preserving, or Sterilizing,   subclasses 50+ or 105+ for chemical apparatus having means to electrically signal a condition of said apparatus or the result of a chemical test.
429, Chemistry: Electrical Current Producing Apparatus, Product, and Process,   subclasses 90+ for battery having measuring, testing, or indicating means.
434, Education and Demonstration,   subclasses 327+ for educational appliances which have a question and hidden answer, some of which signal a correct answer and subclasses 112+ for machines by which a blind person can read printed material, said machine furnishing signals which are a coded representation of the printed material.
441, Buoys, Rafts, and Aquatic Devices,   subclasses 6+ for floating buoys utilized for marine navigation.
446, Amusement Devices: Toys,   appropriate subclasses for various electric and magnetic toys which utilize electric signals, particularly subclass 142 , 242, 454, and 484+.
505, Superconductor Technology: Apparatus, Material, Process,   subclasses 150+ for high temperature (Tc > 30 K) superconducting devices, and particularly subclasses 182+ for light responsive system or subclass 202 for electric communication system.
600, Surgery,   subclasses 300+ for electric diagnostic devices having signals or indicators.
700, Data Processing: Generic Control Systems or Specific Applications,   subclasses 1 through 89for generic data processing control systems, particularly subclass 18 for programming methods or procedures; and subclasses 90-306 for particular application of data processing systems or calculating computers.
702, Data Processing: Measuring, Calibrating, or Testing,   appropriate subclasses for measuring, testing, or calibrating system having significant data processing.
704, Data Processing: Speech Signal Processing, Linguistics, Language Translation, and Audio Compression/Decompression,   subclasses 200+ for artificial intelligence systems that process speech signals.
706, Data Processing: Aritifical Intelligent,   various subclasses for artificial intelligence systems that represent, apply, and acquire knowledge.
708, Electrical Computers: Arithmetic Processing and Calculating,   subclasses 1+ for hybrid computers; subclasses 100+ for digital calculating computers, and subclasses 800+ for analog computers.
709, Electrical Computers and Digital Processing Systems: Multicomputer or data transferring,   appropriate subclassesfor data transfer among multiple computer systems.
714, Error Detection/Correction and Fault Detection/Recovery,   subclasses for apparatus and corresponding processes relating to generic error detection or correction, or fault detection or recovery.

SUBCLASSES

[List of Patents for class 340 subclass 2.1]    2.1Path selection:
 This subclass is indented under subclass 825.  Subject matter having a plurality of alternative communication channels and selection of less than the total number of channels for signal transmission.

SEE OR SEARCH CLASS:

327, Miscellaneous Active Electrical Nonlinear Devices, Circuits and Systems,   subclasses 365 through 508for miscellaneous gating circuits which switch input to output.
370, Multiplex Communications,   subclasses 351 through 430for apparatus or technique for locating a route through a switching network wherein two or more simultaneous information signals are conveyed.
379, Telephonic Communications,   subclasses 219 through 241for plural exchange network or interconnection and subclasses 242-332 for centralized telephone switching system.
710, Electrical Computers and Digital Data, Processing Systems: Input/Output,   subclasses 100 through 132for system intraconnecting, and particularly subclasses 131 and 132 for path selection and switching (e.g., crossbar switching) in a digital data processing system.
  
[List of Patents for class 340 subclass 2.2]    2.2Channel selecting matrix:
 This subclass is indented under subclass 2.1.  Subject matter wherein a communication line is selected using a two or more dimensional array of electrical elements.

SEE OR SEARCH THIS CLASS, SUBCLASS:

14.1through 14.69, for a decoder matrix.
  
[List of Patents for class 340 subclass 2.21]    2.21Plural stages:
 This subclass is indented under subclass 2.2.  Subject matter including multiple levels of plural matrices to form a path through all successive levels.

SEE OR SEARCH THIS CLASS, SUBCLASS:

2.27,for plural matrices in general, subclass 2.6 for plural stage path selection in general, and subclass 14.2 for plural stage decoder matrix.

SEE OR SEARCH CLASS:

370, Multiplex Communications,   subclass 388 for apparatus or technique for locating a route through a multistage switching network wherein two or more simultaneous information signals are conveyed.
  
[List of Patents for class 340 subclass 2.22]    2.22Clos type:
 This subclass is indented under subclass 2.21.  Subject matter wherein the multiple levels are arranged in a nonblocking manner.
(1) Note. A nonblocking matrix is one that always has an available path between a particular input and a particular output.
  
[List of Patents for class 340 subclass 2.23]    2.23Alternate routing:
 This subclass is indented under subclass 2.2.  Subject matter wherein the path through the plural stage matrix system may be modified upon failure of connection between the desired input and output line.

SEE OR SEARCH CLASS:

370, Multiplex Communications,   subclasses 225 through 228for multiplex fault recovery with inoperative channel bypassing.
  
[List of Patents for class 340 subclass 2.24]    2.24Having master control element:
 This subclass is indented under subclass 2.21.  Subject matter including a supervisory element which controls a plural stage matrix.

SEE OR SEARCH THIS CLASS, SUBCLASS:

2.26,for channel selecting matrix having master control element in general.
  
[List of Patents for class 340 subclass 2.25]    2.25Folded:
 This subclass is indented under subclass 2.2.  Subject matter wherein inputs and outputs of the two or more dimensional array are on the same side of the array.

SEE OR SEARCH CLASS:

370, Multiplex Communications,   subclass 361 for apparatus or technique for locating a route through a folded switching network wherein two or more simultaneous information signals are conveyed.
  
[List of Patents for class 340 subclass 2.26]    2.26Having master control element:
 This subclass is indented under subclass 2.2.  Subject matter including a supervisory element that controls a two or more dimensional array.

SEE OR SEARCH THIS CLASS, SUBCLASS:

2.24,for plural stage channel selecting matrix having master control element.
  
[List of Patents for class 340 subclass 2.27]    2.27Plural matrices:
 This subclass is indented under subclass 2.2.  Subject matter including multiple, interconnected, two or more dimensional arrays of electrical elements.

SEE OR SEARCH THIS CLASS, SUBCLASS:

2.21through 2.24, for plural stage communication matrices.
  
[List of Patents for class 340 subclass 2.28]    2.28Crosspoint switch detail (i.e., specific crosspoint):
 This subclass is indented under subclass 2.2.  Subject matter wherein the matrix element is a specific type of switch used to make a connection for signal transmission.
  
[List of Patents for class 340 subclass 2.29]    2.29Semiconductor:
 This subclass is indented under subclass 2.28.  Subject matter wherein the crosspoint element has a conductivity intermediate that of conductors and insulators.

SEE OR SEARCH THIS CLASS, SUBCLASS:

14.6through 14.69, for a semiconductor crosspoint decoder matrix.
  
[List of Patents for class 340 subclass 2.31]    2.31Gas discharge:
 This subclass is indented under subclass 2.28.  Subject matter wherein the crosspoint element comprises a gas discharge tube.

SEE OR SEARCH CLASS:

313, Electric Lamp and Discharge Devices,   subclasses 567 through 643for gas discharge device detail.
  
[List of Patents for class 340 subclass 2.4]    2.4Code or pulse responsive:
 This subclass is indented under subclass 2.1.  Subject matter wherein the channel selection is performed in response to a specified pulse pattern or pulse.

SEE OR SEARCH THIS CLASS, SUBCLASS:

825.57through 825.69, for pulse-responsive selective systems, in general.
  
[List of Patents for class 340 subclass 2.5]    2.5Wiper:
 This subclass is indented under subclass 2.1.  Subject matter wherein a movable electric contact (e.g., a rheostat) is used to establish a channel for signal transmission.

SEE OR SEARCH CLASS:

338, Electrical Resistors,   subclass 68 201 for a mechanically variable type resistor (e.g., rheostat), per se.
  
[List of Patents for class 340 subclass 2.6]    2.6Plural stages:
 This subclass is indented under subclass 2.1.  Subject matter including multiple levels of selectors which are used to establish a path through all successive levels for signal transmission.

SEE OR SEARCH THIS CLASS, SUBCLASS:

2.21through 2.24, for a plural stage channel selecting matrix, and 14.2 for a plural stage decoder matrix.
  
[List of Patents for class 340 subclass 2.7]    2.7Condition of data channel:
 This subclass is indented under subclass 2.1.  Subject matter wherein selection of a channel is based upon the operational condition of system elements.
  
[List of Patents for class 340 subclass 2.71]    2.71Hunting:
 This subclass is indented under subclass 2.7.  Subject matter wherein a search is performed to find a route that is not currently used.
  
[List of Patents for class 340 subclass 2.8]    2.8Data channel selector line:
 This subclass is indented under subclass 2.1.  Subject matter wherein a separate line is used to communicate which of the plurality of possible channels is currently selected for signal transmission.
  
[List of Patents for class 340 subclass 3.1]    3.1Monitoring in addition to control (e.g., supervisory):
 This subclass is indented under subclass 825.  Subject matter wherein a signal representative of the actual status of the controlled device, with respect to an intended controlled function, is transmitted back to the selective signal source.
(1) Note. For classification herein, there must be at least a controller, a sensor, and a controlled device. If only a single controlled device is present, it must exhibit plural functions. Also present must be a control signal and a status signal.
(2) Note. A controller is also called a central or master station.

SEE OR SEARCH CLASS:

700, Data Processing: Generic Control Systems or Specific Applications,   subclasses 1 through 89for a data processing generic control system, apparatus, or process in general, particularly subclasses 9 and 10 for supervisory control in a data processing generic control system, apparatus, or process; and subclasses 90-306 for a data processing specific application, apparatus, or process, particularly subclasses 95-212 for product assembly or manufacturing data processing (especially subclass 169 for supervisory machining control) and subclass 241 for central control of plural dispensing units.
  
[List of Patents for class 340 subclass 3.2]    3.2Synchronization:
 This subclass is indented under subclass 3.1.  Subject matter including a reference timing function for operating plural system components.
(1) Note. The reference timing function often includes a clock-pulse generator.

SEE OR SEARCH THIS CLASS, SUBCLASS:

825.2,825.21, for such subject matter absent monitoring and control

SEE OR SEARCH CLASS:

327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 141 through 163for miscellaneous signal synchronizing.
368, Horology: Time Measuring Systems or Devices,   subclass 47 for wireless synchronization in a plural timepiece system or system device.
370, Multiplex Communications,   appropriate subclasses for synchronization in multiplex communication and particularly subclasses 503 through 520for synchronizing where information is combined or distributed via time channels.
375, Pulse or Digital Communications,   subclasses 354 through 376for pulse or digital communication with synchronization.
713, Electrical Computers and Digital Processing Systems: Support,   subclass 400 and 401 for synchronization of clock or timing signals, data, or pulses in digital processing systems.
  
[List of Patents for class 340 subclass 3.21]    3.21Time slot or packet:
 This subclass is indented under subclass 3.2.  Subject matter wherein the reference timing function includes data frame timing signals such as preamble, header, or frame sync code.

SEE OR SEARCH CLASS:

370, Multiplex Communications,   appropriate subclasses for multiplex communications using time slots or packets.
  
[List of Patents for class 340 subclass 3.22]