H
SECTION H — ELECTRICITY
 H04
ELECTRIC COMMUNICATION TECHNIQUE
 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; coin-freed or check-freed mechanisms G07F)
 H04M

Note(s)

This sub-class includes (a) telephonic communication systems combined with other electrical systems, and (b) testing arrangements peculiar to telephonic communication systems.

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.

 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)
 H04M 1/02
·  Constructional features of telephone sets
 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 1/18
·  ·  Telephone sets modified for use in ships, mines, or other places exposed to adverse environment (H04M 1/19 takes precedence; telephone cabinets per se E 04 H 1/10)
 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 E 04 H 1/10)
 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 signalling identity of wanted subscriber (constructional features H04M 1/23)
 H04M 1/28
·  ·  by interrupting current to generate trains of pulses; by periodically opening and closing contacts to generate trains of pulses
 H04M 1/30
·  ·  ·  Devices which can set up and transmit only one digit at a time
 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 1/42
·  ·  ·  Devices whereby a plurality of digits may be stored simultaneously
 H04M 1/44
·  ·  ·  ·  with provision only for storing one subscriber number at a time by keyboard or dial
 H04M 1/45
·  ·  ·  ·  with provision for storing more than one subscriber number at a time, e.g. using toothed disc
 H04M 1/46
·  ·  ·  ·  ·  using magnetic recording, e.g. on tape
 H04M 1/48
·  ·  ·  ·  ·  using punched cards
 H04M 1/50
·  ·  by generating or selecting currents of predetermined frequencies or combinations of frequencies
 H04M 1/51
·  ·  ·  Devices whereby a plurality of digits may be stored simultaneously
 H04M 1/52
·  ·  Arrangements wherein a dial or equivalent is mechanically coupled to a line selector
 H04M 1/54
·  ·  Arrangements wherein a dial or equivalent generates identifying signals, e.g. in party-line systems
 H04M 1/56
·  Arrangements for indicating the called number at the calling subscriber's set
 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 1/66
·  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 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 (statistical apparatus in general G06F 15/36)
 H04M 3/38
·  Graded-service arrangement, 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 (telegraphy 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
 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)