IPC 6 English version
 
Class H04

SECTION H– ELECTRICITY

H 04ELECTRIC COMMUNICATION TECHNIQUE

 Note

 This class covers electrical communication systems with propagation paths employing light (optical communication), infra-red, ultrasonic, sonic, or infrasonic waves. [4]

H 04 BTRANSMISSION (transmission systems for measured values, control or similar signals G 08 C; coding, decoding or code conversion, in general H 03 M; broadcast communication H 04 H; multiplex systems H 04 J; secret communication H 04 K; transmission of digital information H 04 L) [4]

H 04 HBROADCAST COMMUNICATION (transmission in general H 04 B; multiplex communication H 04 J)

H 04 JMULTIPLEX COMMUNICATION (transmission in general H 04 B; peculiar to transmission of digital information H 04 L 5/00; systems for the simultaneous or sequential transmission of more than one television signal H 04 N 7/08; in exchanges H 04 Q 11/00; stereophonic systems H 04 S)

H 04 KSECRET COMMUNICATION; JAMMING OF COMMUNICATION

H 04 LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (typewriters B 41 J; order telegraphs, fire or police telegraphs G 08 B; visual telegraphy G 08 B, G 08 C; teleautographic systems G 08 C; ciphering or deciphering apparatus per se G 09 C; coding, decoding or code conversion, in general H 03 M; arrangements common to telegraphic and telephonic communication H 04 M; selecting H 04 Q) [4]

H 04 MTELEPHONIC COMMUNICATION (counting mechanisms G 06 M; circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G 08; reels or other take-up devices for cords H 02 G 11/00; multiplex transmission between switching centres H 04 J; selecting arrangements H 04 Q; loudspeakers, microphones, gramophone pick-ups or like electromechanical transducers H 04 R)

H 04 NPICTORIAL COMMUNICATION, e.g. TELEVISION (measuring, testing G 01; systems for autographic writing, e.g. writing telegraphy, which involve following an outline G 08; information storage based on relative movement between record carrier and transducer G 11 B; coding, decoding or code conversion, in general H 03 M; broadcast distribution or the recording of use made thereof H 04 H) [4]

H 04 QSELECTING (switches, relays, selectors H 01 H; electronic switches H 03 K 17/00)

H 04 RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS (generating mechanical vibrations in general B 06 B; transducers for measuring particular variables G 01; transducers in clocks G 04; producing sounds with frequency not determined by supply frequency G 10 K; transducers in recording or reproducing heads G 11 B; transducers in motors H 02) [6]

H 04 SSTEREOPHONIC SYSTEMS (information storage on discs or tapes G 11 B; broadcast systems for the distribution of stereophonic information H 04 H 5/00; multiplex systems in general H 04 J) [3]