with voice-band signalling frequencies

Introduced: January 1980

Last revised: January 2006

Full Title

Details of selecting apparatus or arrangements > Electrical details > Signalling arrangements; Manipulation of signalling currents > using AC > with voice-band signalling frequencies

Classification Context

Section:: ELECTRICITY
Class:: ELECTRIC COMMUNICATION TECHNIQUE
Subclass:: SELECTING

3 direct subcodes

Child Classifications

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H04Q 1/446 using one signalling frequency
H04Q 1/45 using multi-frequency signalling
H04Q 1/46 comprising means for distinguishing between a signalling current of predetermined frequency and a complex current containing that frequency, e.g. speech current

Top Applicants

Top 10 applicants by patent filingsfor class H04, 2013–2023, worldwide · Source: EPO PATSTAT

QUALCOMM US 97,396
HUAWEI TECHNOLOGIES COMPANY CN 96,502
SAMSUNG ELECTRONICS COMPANY KR 86,981
TELEFONAKTIEBOLAGET LM ERICSSON (PUBL) SE 55,869
HUAWEI TECHNOLOGIES COMPANY 55,349
LG ELECTRONICS KR 53,649
CANON 33,341
SONY CORPORATION JP 32,761
ZTE CORPORATION CN 32,274
GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORPORATION 28,327