H04Q 1/444
With voice-band signalling frequencies
Official title: with voice-band signalling frequencies
H04Q1/444 (With voice-band signalling frequencies) appears on 624 US grants and 196 published applications in this corpus.
Search patents in H04Q- Granted patents
- 624
- Published applications
- 196
- Assignees
- 300
- Inventors
- 1,000
- Latest grant
- 11 Aug 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 29 | 0 |
| 1977 | 27 | 0 |
| 1978 | 17 | 0 |
| 1979 | 9 | 0 |
| 1980 | 19 | 0 |
| 1981 | 7 | 0 |
| 1982 | 12 | 0 |
| 1983 | 14 | 0 |
| 1984 | 8 | 0 |
| 1985 | 12 | 0 |
| 1986 | 16 | 0 |
| 1987 | 13 | 0 |
| 1988 | 10 | 0 |
| 1989 | 12 | 0 |
| 1990 | 11 | 0 |
| 1991 | 4 | 0 |
| 1992 | 11 | 0 |
| 1993 | 16 | 0 |
| 1994 | 21 | 0 |
| 1995 | 21 | 0 |
| 1996 | 14 | 0 |
| 1997 | 15 | 0 |
| 1998 | 22 | 0 |
| 1999 | 21 | 0 |
| 2000 | 19 | 0 |
| 2001 | 17 | 7 |
| 2002 | 19 | 29 |
| 2003 | 18 | 23 |
| 2004 | 23 | 25 |
| 2005 | 16 | 13 |
| 2006 | 25 | 7 |
| 2007 | 14 | 17 |
| 2008 | 5 | 6 |
| 2009 | 10 | 7 |
| 2010 | 12 | 8 |
| 2011 | 10 | 13 |
| 2012 | 10 | 3 |
| 2013 | 14 | 4 |
| 2014 | 11 | 5 |
| 2015 | 12 | 5 |
| 2016 | 4 | 3 |
| 2017 | 2 | 2 |
| 2018 | 5 | 4 |
| 2019 | 4 | 2 |
| 2020 | 3 | 4 |
| 2021 | 4 | 1 |
| 2022 | 1 | 3 |
| 2023 | 0 | 0 |
| 2024 | 2 | 4 |
| 2025 | 1 | 0 |
| 2026 | 2 | 1 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- System, method, and apparatus for detecting call interception11 Aug 2026US 12,707,265 B2University of Florida Research Foundation, Inc.
- Call classification through analysis of DTMF events5 May 2026US 12,621,382 B2Pindrop Security, Inc.
- Method and apparatus for transmitting PLCP frame in wireless local area network system3 Jun 2025US 12,323,283 B2Telefonaktiebolaget LM Ericsson (publ)
- Call classification through analysis of DTMF events18 Jun 2024US 12,015,731 B2Pindrop Security, Inc.
- Method and apparatus for transmitting PLCP frame in wireless local area network system13 Feb 2024US 11,902,068 B2Telefonaktiebolaget LM Ericsson (publ)
- Call classification through analysis of dtmf events17 Sep 2026US 2026/0281227 A1Pindrop Security, Inc.
- System, method, and apparatus for detecting call interception19 Dec 2024US 2024/0422545 A1University of Florida Research Foundation, Inc.
- Call classification through analysis of dtmf events26 Sep 2024US 2024/0323270 A1Pindrop Security, Inc.
- Method and Apparatus for Transmitting PLCP Frame in Wireless Local Area Network System11 Jul 2024US 2024/0235909 A9Telefonaktiebolaget LM Ericsson (publ)
- Method and Apparatus for Transmitting PLCP Frame in Wireless Local Area Network System25 Apr 2024US 2024/0137255 A1Telefonaktiebolaget LM Ericsson (publ)
Most cited
By later US patents
- Telephone system for connecting a customer to a supplier of goods744US 4,757,267 AApplied Telematics, Inc. · 1988
- Call routing based on the caller's mood398US 6,411,687 B1Mitel Knowledge Corporation · 2002
- Method and apparatus for telephonically accessing and navigating the internet268US 5,953,392 ANetphonic Communications, Inc. · 1999
- Speech encoding in a client server system250US 6,594,347 B1International Business Machines Corporation · 2003
- Information storage device for storing personal identification information232US 5,825,871 ASmart Tone Authentication, Inc. · 1998