H
SECTION H — ELECTRICITY
 H04
ELECTRIC COMMUNICATION TECHNIQUE
 H04B
TRANSMISSION (broadcast communication H04H; multiplex systems H04J; secret communication H04K)
 H04B

Note(s)

This sub-class deals with the transmission of information-carrying signals, the transmission being independent of the nature of the information, and includes monitoring and testing arrangements and the suppression and limitation of noise and interference.


 H04H
BROADCAST COMMUNICATION (transmission in general H04B; multiplex communication H04J)
 H04H

Note(s)

This sub-class deals with (a) the distribution of entertainment or informative matter simultaneously to a number of receiving stations over transmission lines or over radio waves, and (b) the recording of the use made of the broadcast service.


 H04J
MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L 5/00; systems for transmitting television signals simultaneously or sequentially H04N 7/08; in exchanges H04Q 11/00; stereophonic systems H04S)
 H04J

Note(s)

This sub-class deals with (a) circuits or apparatus for combining or dividing signals for the purpose of transmitting them simultaneously or sequentially over the same transmission path, and (b) monitoring arrangements therefor.


 H04K
SECRET COMMUNICATION; JAMMING OF COMMUNICATION
 H04K

Note(s)

The term "secret communication" includes secret line and radiation transmission systems, i.e. those in which apparatus at the transmitting station modifies the signal in such a way that the information cannot be intelligibly received without corresponding modifying apparatus at the receiving station.


 H04L
TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (typewriters B41J; order telegraphs, fire or police telegraphs G08B; visual telegraphy G08B, G08C; teleautographic systems G08C; arrangements common to telegraphic and telephonic communication H04M; selecting H04Q)
 H04L

Note(s)

This sub-class deals with transmission of signals having been supplied in digital form and includes data transmission, telegraphic communication, and methods or arrangements for monitoring.


 H04M
TELEPHONIC COMMUNICATION (counting mechanisms G06M; circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08; reels or other take-up devices for cords H02G 11/00; multiplex transmission between switching centres H04J; selecting arrangements H04Q; transducers H04R)
 H04M

Note(s)

  1. This sub-class includes (a) telephonic communication systems combined with other electrical systems, and (b) testing arrangements peculiar to telephonic communication systems.
  2. In this sub-class:
    1. "Subscriber" is a general term for terminal equipment, e.g. telephone for public use.
    2. "Substation" means a subscriber of monitoring equipment which may connect a single subscriber to a line without choice as to subscriber.
    3. A "satellite" is a type of exchange the operation of which depends upon control signals received from a supervisory exchange.
    4. "Switching centres" include exchanges and satellites.

 H04N
PICTORIAL COMMUNICATION; TELEVISION (measuring, testing G01; systems for autographic writing, e.g. writing telegraphy, which involve following an outline G08; information storage based on relative movement between record carrier and transducer G11B; broadcast distribution or the recording of use made thereof H04H)
 H04N

Note(s)

  1. This sub-class deals with the transmission of pictures or their transient or permanent reproduction either locally or remotely, by methods involving both the following steps:

    Step (a): the scanning of a picture, i.e. the analysis of the whole of a picture-containing area by resolving it into an area or a plurality of areas of which at least one of the two dimensions is elemental, simultaneously or in a sequence, and the derivation in response thereto of a picture-representative electric signal;

    Step (b): the reproduction of the whole of a picture-containing area by the reproduction in response to a picture-representative electric signal of an area or a plurality of areas of which at least one of the two dimensions is elemental, simultaneously or in sequence.

  2. In this sub-class, "pictorial communication systems" are those systems for the transmission and reproduction of arbitrarily composed pictures in which the local light variations composing a picture are not subject to variation with time, e.g. documents (both written and printed), maps, charts, photographs (other than cinematograph films).
  3. In this sub-class, "television systems" are those systems for the transmission and reproduction of arbitrarily composed pictures in which the local light variations composing a picture may change with time, e.g. natural "live" scenes, recordings of such scenes such as cinematograph films.
  4. This sub-class includes circuits specially designed for dealing with television or pictorial communication signals, as distinct from merely signals of a particular frequency range.
  5. This sub-class does not include the following subject matter:
    1. Circuits or other parts of systems which form the subject of other sub-classes, which are dealt with in the corresponding sub-classes, e.g. H03C, H03F, H03J, H04B, H04H.
    2. Systems in which legible alphanumeric or like character forms are analysed according to Step (a) to derive an electric signal from which the character is recognised by comparison with stored information, which are dealt with in G06K.
    3. Systems for the direct photographic copying of an original picture in which an electric signal representative of the picture is derived according to Step (a) and employed to modify the operation of the system, which are dealt with in G03.
    4. Systems for the reproduction according to Step (b) of pictures comprising alphanumeric or like character forms but involving the production of the equivalent of a signal which would be derived by Step (a), e.g. by cams, punched card or tape, coded control signal, or other means, which are dealt with in the sub-class for the application, e.g. G01D, G06F, H04L.
    5. Systems involving Step (a) or Step (b) for producing (1) engraved, indented, apertured, or otherwise formed printing surfaces, or (2) photographs specially arranged for producing such printing surfaces or for use generally in printing or duplication, which are dealt with in G03F.
    6. Systems involving Step (a) or Step (b) but otherwise specially modified for printing or duplication, which are dealt with in such sub-classes as B41M, G03C, G03F.
  6. Systems for the reproduction according to Step (b) of pictures comprising alphanumeric or like character forms and involving the generation according to Step (a) of picture-representative electric signals from a pre-arranged assembly of such characters, or records thereof, forming an integral part of the systems, are dealt with in the sub-class for the application, e.g. B41B, G06K, H04N.

 H04Q
SELECTING (switches, relays, selectors H01H; electronic switches H03K 17/00)
 H04Q

Note(s)

  1. This sub-class deals with methods, circuits, or apparatus for establishing selectively a connection between a desired number of stations (normally two), or between a main station and a desired number of substations (normally one) for the purpose of transferring information via this connection after it has been established. The sub-class also deals with selective calling arrangements over connections already established. In either case, the connection may be by means of electric conductors or electromagnetic waves.
  2. In this sub-class:
    1. "Subscriber" is a general term for terminal equipment, e.g. telephone for public use.
    2. "Substation" means a subscriber or monitoring equipment which may connect a single subscriber to a line without choice as to subscriber.
    3. A "satellite" is a kind of exchange the operation of which depends upon control signals received from a supervisory exchange.
    4. "Switching centres" include exchanges and satellites.

 H04R
ELECTROMECHANICAL TRANSDUCERS (for performing mechanical work B06B; use of transducers as sensing elements for measuring G01, G04; construction or circuits of vibrators whose output is of frequency unrelated to that of the electric supply G10K; recording or reproducing heads incorporating transducers G11B; dynamo-electric machines H02K)
 H04R

Note(s)

This sub-class deals with (a) instruments capable of converting sonic, ultrasonic, or infrasonic waves, or other mechanical vibrations into variations of electric current or voltage or vice versa, (b) instruments actuated by variations of electric current or voltage for cutting grooves in records, (c) circuits for the instruments of (a) and (b), (d) deaf-aid sets, (e) public address systems, and (f) monitoring or testing the equipment of (a) to (e).


 H04S
STEREOPHONIC SYSTEMS (information storage on discs or tapes G11B; broadcast systems for the distribution of stereophonic information H04H 5/00; multiplex systems in general H04J)  [3]
 H04S

Note(s)

In this sub-class, the term "stereophonic systems" covers quadraphonic or similar systems. [3]