CPC Subgroup
H04Q 1/446 using one signalling frequency (H04Q1/46 takes precedence)
Full Title
Details of selecting apparatus or arrangements > Electrical details > Signalling arrangements; Manipulation of signalling currents (multiplex systems providing for calling or supervisory signals H04J1/14, H04J3/12) > using alternate current (H04Q1/50 takes precedence) > with voice-band signalling frequencies > using one signalling frequency (H04Q1/46 takes precedence)
2 direct subcodes
Child Classifications
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- H04Q 1/448 with conversion of a single frequency signal into a digital signal
Top Applicants
Top 10 applicants by patent filingsfor class H04, 2013–2023, worldwide · Source: EPO PATSTAT
- HUAWEI TECHNOLOGIES COMPANY CN 101,476
- QUALCOMM US 101,139
- SAMSUNG ELECTRONICS COMPANY KR 96,655
- TELEFONAKTIEBOLAGET LM ERICSSON (PUBL) SE 57,744
- LG ELECTRONICS KR 55,253
- HUAWEI TECHNOLOGIES COMPANY 54,181
- SONY CORPORATION JP 35,309
- ZTE CORPORATION CN 32,950
- INTEL CORPORATION US 27,533
- GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORPORATION CN 27,498