IPC 7 English version H04M 3/00-H04M 19/08

IPC ⁷ English version

H04M - H04M 1/82

H04M00300-H04M01908

SECTION H – ELECTRICITY

H 04

ELECTRIC COMMUNICATION TECHNIQUE

H 04 M

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; loudspeakers, microphones, gramophone pick-ups or like electromechanical transducers H04R)

Automatic or semi-automatic exchanges

Ringing or otherwise calling substations (selective calling H04Q)

calling signal supplied from final selector

calling signal supplied from subscriber's line circuit

Indicating faults in circuits or apparatus

providing fault- or trouble-signals

Marking faulty circuits "busy"; Enabling equipment to disengage itself from faulty circuits

Signalling existence of persistent "off-hook" condition

with lock-out or secrecy provision in party-line systems

with means for reducing interference; with means for reducing effects due to line faults

with means for interrupting existing connections; with means for breaking-in on conversations

Supervisory, monitoring, or testing arrangements

with provision for checking the normal operation

with means for applying test signals

Automatic routine testing

for subscribers' lines

for lines between exchanges

Testing for cross-talk (in lines generally H04B)

Statistical metering, e.g. recording occasions when traffic exceeds capacity of trunks (digital computers for evaluating statistical data G06F 17/18)

Graded-service arrangements, i.e. some subscribers prevented from establishing certain connections (queuing arrangements H04Q 3/64)

Applications of speech amplifiers

Systems providing special services or facilities to subscribers

424

Arrangements for automatic redialling (at the subscriber's set H04M 1/27) [7]

428

Arrangements for placing incoming calls on hold [7]

432

Arrangements for calling a subscriber at a specific time, e.g. morning call service [7]

436

Arrangements for screening incoming calls [7]

Additional connecting arrangements for providing access to frequently-wanted subscribers, e.g. abbreviated dialling (at the subscriber's set H04M 1/27; automatic redialling H04M 3/424) [1,7]

Arrangements for calling a number of substations in a predetermined sequence until an answer is obtained

Arrangements for recalling a calling subscriber when the wanted subscriber ceases to be busy

487

Arrangements for providing information services, e.g. recorded voice services, time announcement [7]

493

Interactive information services, e.g. directory enquiries [7]

Centralised arrangements for answering calls; Centralised arrangements for recording messages for absent or busy subscribers (H04M 3/487 takes precedence; centralised dictation systems H04M 11/10) [1,7]

Centralised call answering arrangements requiring operator intervention [7]

Arrangements for routing dead number calls to operators

523

with call distribution or queuing [7]

527

Centralised call answering arrangements not requiring operator intervention [7]

Centralised arrangements for recording incoming messages [7]

533

Voice mail systems [7]

537

Arrangements for indicating the presence of a recorded message [7]

Arrangements for diverting calls for one subscriber to another predetermined subscriber

Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities (video conference systems H04N 7/15)

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 (substation line holding circuits H04M 1/80) [1,7]

Semi-automatic systems, i.e. in which the numerical selection of the outgoing line is under the control of an operator

Keyboard equipment

Arrangements for signalling the number or class of the calling line to the operator (between operators in inter-exchange working H04M 5/18)

Manual exchanges (substation equipment in general H04M 1/00)

Constructional details (jacks, jack-plugs H01R 24/04)

Arrangements for indicating calls or supervising connections for calling or clearing

affording automatic call distribution

using connecting means other than cords

using separate plug for each subscriber

Ringing or otherwise calling substations

Applications of speech amplifiers

with means for reducing interference; with means for reducing effects due to line faults

Arrangements for signalling the class or number of called or calling line from one exchange to another

Number-indicating arrangements for incoming lines

Interconnection arrangements between switching centres (transmission arrangements in general H04B)

for compensating differences of ground potential

for compensating differences of line impedance

using auxiliary connections for control or supervision

for phantom working

for two-way working, i.e. calls may be set-up in either direction over the same connection

for working between exchanges having different types of switching equipment, e.g. power-driven and step by step, decimal and non-decimal

in systems involving main and subordinate switching centres (current supply source at subordinate switching centre charged from main exchange H04M 19/06)

in systems employing carrier frequencies

Interconnection arrangements not involving centralised switching

involving a common line for all parties

involving a separate line for each pair of parties

involving combinations of interconnecting lines

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)

with switching of direction of transmission by voice frequency

11/

Telephonic communication systems adapted for combination with other electrical systems

11/

with bell or annunciator systems (such systems in general G08)

11/

with fire, police, burglar, or other alarm systems (such systems in general G08)

11/

Simultaneous speech and telegraphic or other data transmission over the same conductors (transmission of digital information in general H04L)

11/

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)

11/

with dictation recording and playback systems (such systems in general G11B)

13/

Party-line systems (substation equipment H04M 1/00; exchange equipment H04M 3/00, H04M 5/00; metering arrangements H04M 15/36)

15/

Metering arrangements; Time-controlling arrangements; Time-indicating arrangements

15/

Severing connection after predetermined time

15/

Recording calls in printed, perforated, or other permanent form

15/

Recording class or number of calling or of called party

15/

Metering calls to called party

15/

Metering calls from calling party

15/

Discriminative metering

15/

according to class of calling party

15/

according to connection obtained

15/

according to duration of call

15/

Operator's time recording or indicating arrangements

15/

according to time of day

15/

preventing metering of tax-free calls to certain lines, e.g. to fire or ambulance stations

15/

Meter at exchange controlled by operator

15/

with meter at substation

15/

Meter not controlled from exchange

15/

Metering arrangements for satellites or concentrators which connect one or more exchange lines with a group of local lines

15/

Metering arrangements for private branch exchanges

15/

Metering arrangements for party-lines

15/

Metering by apparatus not of the mechanical step-by-step counter type

17/

Prepayment telephone systems (using a coded card to authorise calls from a telephone set H04M 1/675) [1,7]

17/

Coin-freed or check-freed systems (coin-freed or check-freed apparatus in general G07F)

19/

Current supply arrangements for telephone systems (for selecting equipment H04Q 1/28)

19/

providing ringing current or supervisory tones, e.g. dialling tone, busy tone

19/

Ringing-current generated at substation

19/

Current supply source at subordinate switching centre charged from main exchange

19/

Current supply source at substation (battery saving arrangements for cordless telephones H04M 1/73; generating ringing current H04M 19/04) [1,7]

H04M - H04M 1/82