H
SECTION H — ELECTRICITY
 H04
ELECTRIC COMMUNICATION TECHNIQUE
 H04

Note(s)

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

 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 subclass covers:
    • telephonic communication systems combined with other electrical systems;
    • testing arrangements peculiar to telephonic communication systems.
  2. In this subclass, the following terms or expressions are used with the meanings indicated:
    • "subscriber" is a general term for terminal equipment, e.g. telephone for public use;
    • "substation" means a subscriber or monitoring equipment which may connect a single subscriber to a line without choice as to subscriber;
    • "satellite" is a type of exchange the operation of which depends upon control signals received from a supervisory exchange;
    • "switching centres" includes exchanges and satellites.
 H04M 1/00
Substation equipment, e.g. for use by subscribers; Analogous equipment at exchanges (prepayment telephone coin boxes H04M 17/00; current supply arrangements H04M 19/00; keyboard switches in general H01H 13/70, H03K 17/94)
 H04M 1/02
·  Constructional features of telephone sets
 H04M 1/03
·  ·  Constructional features of telephone transmitters or receivers, e.g. telephone hand-sets (transducers in general H04R 1/00)  [2]
 H04M 1/04
·  ·  Supports for telephone transmitters or receivers (for transducers in general H04R 1/00)
 H04M 1/05
·  ·  ·  adapted for use on head, throat, or breast
 H04M 1/06
·  ·  ·  Hooks; Cradles
 H04M 1/08
·  ·  ·  ·  associated with switches operated by weight of receiver or hand-set
 H04M 1/10
·  ·  ·  ·  associated with switches operated by magnetic effect due to proximity of receiver or hand-set
 H04M 1/11
·  ·  Supports for sets, e.g. incorporating armrests
 H04M 1/12
·  ·  ·  Adjustable supports, e.g. extensible
 H04M 1/13
·  ·  ·  ·  pantographic
 H04M 1/14
·  ·  ·  with resilient means to eliminate extraneous vibrations
 H04M 1/15
·  ·  Protection of telephone cord; Guiding telephone cord; Winding-up telephone cord (in general H02G 11/00)
 H04M 1/17
·  ·  Hygienic or sanitary devices on telephone equipment (for mouthpieces or earpieces per se H04R 1/12)  [2]
 H04M 1/18
·  ·  Telephone sets modified for use in ships, mines, or other places exposed to adverse environment (H04M 1/19 takes precedence; telephone cabinets per se E04H 1/14)
 H04M 1/19
·  ·  Arrangements of transmitters, receivers, or complete sets to prevent eavesdropping, to attenuate local noise or to prevent undesired transmission; Special mouthpieces or receivers therefor (circuit arrangements for preventing eavesdropping H04M 1/68; telephone cabinets per se E04H 1/14)
 H04M 1/20
·  ·  Arrangements for preventing acoustic feedback (H04M 1/62 takes precedence)
 H04M 1/21
·  ·  Combinations with auxiliary equipment, e.g. with clock, with memoranda pad
 H04M 1/22
·  ·  Illuminating; Arrangements for improving visibility of characters on dials
 H04M 1/23
·  ·  Construction or mounting of dials or of equivalent devices; Means for facilitating the use thereof (by improving visibility H04M 1/22)
 H04M 1/24
·  Arrangements for testing (measuring electric values G01R; testing transducers H04R 29/00)
 H04M 1/26
·  Devices for calling a subscriber (coding in connection with keyboards or like devices, in general H03M 11/00)
 H04M 1/27
·  ·  Devices whereby a plurality of signals may be stored simultaneously  [2]
 H04M 1/272
·  ·  ·  with provision for storing only one subscriber number at a time, e.g. by keyboard or dial  [2]
 H04M 1/274
·  ·  ·  with provision for storing more than one subscriber number at a time, e.g. using toothed disc  [2]
 H04M 1/276
·  ·  ·  ·  using magnetic recording, e.g. on tape  [2]
 H04M 1/278
·  ·  ·  ·  using punched cards or tapes  [2]
 H04M 1/30
·  ·  Devices which can set up and transmit only one digit at a time
 H04M 1/31
·  ·  ·  by interrupting current to generate trains of pulses; by periodically opening and closing contacts to generate trains of pulses  [2]
 H04M 1/315
·  ·  ·  ·  Clutches, spring assemblies, speed regulators, e.g. centrifugal brakes (H04M 1/32-H04M 1/40 take precedence)  [3]
 H04M 1/32
·  ·  ·  ·  Locking setting devices during transmission to prevent interference by user
 H04M 1/34
·  ·  ·  ·  Lost-motion or other arrangements for ensuring a pause between successive digit transmissions
 H04M 1/36
·  ·  ·  ·  Preventing the sending of predetermined numbers
 H04M 1/38
·  ·  ·  ·  Pulses transmitted by a movement variably limited by the setting of a stop
 H04M 1/40
·  ·  ·  ·  wherein the setting-operation short-circuits or open-circuits the transmitting mechanism during a variable part of a cycle
 H04M 1/50
·  ·  ·  by generating or selecting currents of predetermined frequencies or combinations of frequencies  [2]
 H04M 1/515
·  ·  by generating or selecting other signals than trains of pulses of similar shape or other signals than currents of one or more different frequencies, e.g. generation of dc signals of alternating polarity, coded pulses, impedance dialling  [2]
 H04M 1/52
·  ·  Arrangements wherein a dial or equivalent is mechanically coupled to a line selector
 H04M 1/53
·  ·  Generation of additional signals, e.g. additional pulses  [2]
 H04M 1/54
·  ·  ·  Arrangements wherein a dial or equivalent generates identifying signals, e.g. in party-line systems  [2]
 H04M 1/56
·  Arrangements for indicating or recording the called number at the calling subscriber's set
 H04M 1/57
·  Arrangements for indicating or recording the number of the calling subscriber at the called subscriber's set (at the operator set in a manual exchange H04M 5/20)  [2]
 H04M 1/58
·  Anti-side-tone circuits (hybrid circuits for carrier-frequency operation H04B 1/00)
 H04M 1/60
·  including speech amplifiers
 H04M 1/62
·  ·  Constructional arrangements
 H04M 1/64
·  Automatic arrangements for answering calls; Automatic arrangements for recording messages for absent subscribers (centralised dictation systems H04M 11/10)
 H04M 1/65
·  ·  Automatic arrangements for recording messages for absent subscribers  [2]
 H04M 1/66
·  with means for preventing unauthorised or fraudulent calling
 H04M 1/68
·  Circuit arrangements for preventing eavesdropping
 H04M 1/70
·  ·  Lock-out or secrecy arrangements in party-line systems
 H04M 1/72
·  Substation extension arrangements
 H04M 1/74
·  with means for reducing interference; with means for reducing effects due to line faults
 H04M 1/76
·  Compensating for differences in line impedance (in general H04B)
 H04M 1/78
·  Circuit arrangements in which low-frequency speech signals proceed in one direction on the line, while speech signals proceeding in the other direction on the line are modulated on a high-frequency carrier signal (repeater circuits H04B 3/38)  [2]
 H04M 3/00
Automatic or semi-automatic exchanges
 H04M 3/02
·  Ringing or otherwise calling substations (selective calling H04Q)
 H04M 3/04
·  ·  calling signal supplied from final selector
 H04M 3/06
·  ·  calling signal supplied from subscriber's line circuit
 H04M 3/08
·  Indicating faults in circuits or apparatus
 H04M 3/10
·  ·  providing fault- or trouble-signals
 H04M 3/12
·  ·  Marking faulty circuits "busy"; Enabling equipment to disengage itself from faulty circuits
 H04M 3/14
·  ·  Signalling existence of persistent "off-hook" condition
 H04M 3/16
·  with lock-out or secrecy provision in party-line systems
 H04M 3/18
·  with means for reducing interference; with means for reducing effects due to line faults
 H04M 3/20
·  with means for interrupting existing connections; with means for breaking-in on conversations
 H04M 3/22
·  Supervisory, monitoring, or testing arrangements
 H04M 3/24
·  ·  with provision for checking the normal operation
 H04M 3/26
·  ·  with means for applying test signals
 H04M 3/28
·  ·  ·  Automatic routine testing
 H04M 3/30
·  ·  ·  ·  for subscribers' lines
 H04M 3/32
·  ·  ·  ·  for lines between exchanges
 H04M 3/34
·  ·  ·  Testing for cross-talk (in lines generally H04B)
 H04M 3/36
·  ·  Statistical metering, e.g. recording occasions when traffic exceeds capacity of trunks (digital computers for evaluating statistical data G06F 15/36)
 H04M 3/38
·  Graded-service arrangements, i.e. some subscribers prevented from establishing certain connections (queueing arrangements H04Q 3/64)
 H04M 3/40
·  Applications of speech amplifiers
 H04M 3/42
·  Systems providing special services to subscribers
 H04M 3/44
·  ·  Additional connecting arrangements for providing access to frequently-wanted subscribers
 H04M 3/46
·  ·  Arrangements for calling a number of substations in a predetermined sequence until an answer is obtained
 H04M 3/48
·  ·  Arrangements for recalling a calling subscriber when the wanted subscriber ceases to be busy
 H04M 3/50
·  ·  Centralised arrangements for answering calls; Centralised arrangements for recording messages for absent subscribers (centralised dictation systems H04M 11/10)
 H04M 3/52
·  ·  ·  Arrangements for routing dead-number calls to operators
 H04M 3/54
·  ·  Arrangements for diverting calls for one subscriber to another predetermined subscriber
 H04M 3/56
·  ·  Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities
 H04M 3/58
·  ·  Arrangements for transferring received calls from one subscriber to another; Arrangements affording interim conversations between either the calling or the called party and a third party
 H04M 3/60
·  Semi-automatic systems, i.e. in which the numerical selection of the outgoing line is under the control of an operator
 H04M 3/62
·  ·  Keyboard equipment
 H04M 3/64
·  ·  Arrangements for signalling the number or class of the calling line to the operator (between operators in inter-exchange working H04M 5/18)
 H04M 5/00
Manual exchanges (substation equipment in general H04M 1/00)
 H04M 5/02
·  Constructional details (jacks, jack-plugs H01R 17/00, H01R 21/00)
 H04M 5/04
·  Arrangements for indicating calls or supervising connections for calling or clearing
 H04M 5/06
·  ·  affording automatic call distribution
 H04M 5/08
·  using connecting means other than cords
 H04M 5/10
·  using separate plug for each subscriber
 H04M 5/12
·  Ringing or otherwise calling substations
 H04M 5/14
·  Applications of speech amplifiers
 H04M 5/16
·  with means for reducing interference; with means for reducing effects due to line faults
 H04M 5/18
·  Arrangements for signalling the class or number of called or calling line from one exchange to another
 H04M 5/20
·  ·  Number-indicating arrangements for incoming lines
 H04M 7/00
Interconnection arrangements between switching centres (transmission arrangements in general H04B)
 H04M 7/02
·  modified to compensate for differences of ground potential
 H04M 7/04
·  modified to compensate for differences of line impedance
 H04M 7/06
·  using auxiliary connections for control or supervision
 H04M 7/08
·  adapted for phantom working
 H04M 7/10
·  adapted for two-way working, i.e. calls may be set-up in either direction over the same connection
 H04M 7/12
·  adapted for working between exchanges having different types of switching equipment, e.g. power-driven and step by step, decimal and non-decimal
 H04M 7/14
·  in systems involving main and subordinate switching centres (current supply source at subordinate switching centre charged from main exchange H04M 19/06)
 H04M 7/16
·  in systems employing carrier frequencies
 H04M 9/00
Interconnection arrangements not involving centralised switching
 H04M 9/02
·  involving a common line for all parties
 H04M 9/04
·  involving a separate line for each pair of parties
 H04M 9/06
·  involving combinations of interconnecting lines
 H04M 9/08
·  Two-way loud-speaking telephone systems with means for suppressing echoes or otherwise conditioning for one or other direction of traffic (for line transmission in general H04B 3/20)
 H04M 9/10
·  ·  with switching of direction of transmission by voice frequency
 H04M 11/00
Telephonic communication systems adapted for combination with other electrical systems
 H04M 11/02
·  with bell or annunciator systems (such systems in general G08)
 H04M 11/04
·  with fire, police, burglar, or other alarm systems (such systems in general G08)
 H04M 11/06
·  Simultaneous speech and telegraphic or other data transmission over the same conductors (transmission of digital information in general H04L)
 H04M 11/08
·  adapted for optional reception of entertainment or informative matter (systems in which the information is continuously available on a carrier over the whole network H04H 1/08)
 H04M 11/10
·  with dictation recording and playback systems (such systems in general G11B)
 H04M 13/00
Party-line systems (substation equipment H04M 1/00; exchange equipment H04M 3/00, H04M 5/00; metering arrangements H04M 15/36)
 H04M 15/00
Metering arrangements; Time-controlling arrangements; Time-indicating arrangements (counters per se G06M, H03K)
 H04M 15/02
·  Severing connection after predetermined time
 H04M 15/04
·  Recording calls in printed, perforated, or other permanent form
 H04M 15/06
·  ·  Recording class or number of calling or of called party
 H04M 15/08
·  Metering calls to called party
 H04M 15/10
·  Metering calls from calling party
 H04M 15/12
·  ·  Discriminative metering
 H04M 15/14
·  ·  ·  according to class of calling party
 H04M 15/16
·  ·  ·  according to connection obtained
 H04M 15/18
·  ·  ·  according to duration of call
 H04M 15/20
·  ·  ·  ·  Operator's time recording or indicating arrangements
 H04M 15/22
·  ·  ·  according to time of day
 H04M 15/24
·  ·  ·  preventing metering of tax-free calls to certain lines, e.g. to fire or ambulance stations
 H04M 15/26
·  ·  Meter at exchange controlled by operator
 H04M 15/28
·  with meter at substation
 H04M 15/30
·  ·  Meter not controlled from exchange
 H04M 15/32
·  Metering arrangements for satellites or concentrators which connect one or more exchange lines with a group of local lines
 H04M 15/34
·  Metering arrangements for private branch exchanges
 H04M 15/36
·  Metering arrangements for party-lines
 H04M 15/38
·  Metering by apparatus not of the mechanical step-by-step counter type
 H04M 17/00
Prepayment telephone systems
 H04M 17/02
·  Coin-freed or check-freed systems (coin-freed or check-freed apparatus per se G07F)
 H04M 19/00
Current supply arrangements for telephone systems (for selecting equipment H04Q 1/28)
 H04M 19/02
·  providing ringing current or supervisory tones, e.g. dialling tone, busy tone
 H04M 19/04
·  ·  Ringing-current generated at substation
 H04M 19/06
·  Current supply source at subordinate switching centre charged from main exchange
 H04M 19/08
·  Current supply source at substation (generating ringing current H04M 19/04)