H04M 3/12
Marking faulty circuits "busy"
Official title: Marking faulty circuits "busy"; Enabling equipment to disengage itself from faulty circuits {; Using redundant circuits; Response of a circuit, apparatus or system to an error}
H04M3/12 (Marking faulty circuits "busy") appears on 291 US grants and 179 published applications in this corpus.
Search patents in H04M- Granted patents
- 291
- Published applications
- 179
- Assignees
- 142
- Inventors
- 541
- Latest grant
- 7 Apr 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1977 | 2 | 0 |
| 1978 | 1 | 0 |
| 1979 | 0 | 0 |
| 1980 | 0 | 0 |
| 1981 | 0 | 0 |
| 1982 | 1 | 0 |
| 1983 | 0 | 0 |
| 1984 | 2 | 0 |
| 1985 | 1 | 0 |
| 1986 | 1 | 0 |
| 1987 | 0 | 0 |
| 1988 | 2 | 0 |
| 1989 | 1 | 0 |
| 1990 | 2 | 0 |
| 1991 | 1 | 0 |
| 1992 | 2 | 0 |
| 1993 | 5 | 0 |
| 1994 | 3 | 0 |
| 1995 | 2 | 0 |
| 1996 | 5 | 0 |
| 1997 | 3 | 0 |
| 1998 | 2 | 0 |
| 1999 | 19 | 0 |
| 2000 | 15 | 0 |
| 2001 | 18 | 6 |
| 2002 | 19 | 22 |
| 2003 | 17 | 14 |
| 2004 | 19 | 15 |
| 2005 | 20 | 15 |
| 2006 | 19 | 26 |
| 2007 | 8 | 10 |
| 2008 | 6 | 15 |
| 2009 | 14 | 4 |
| 2010 | 12 | 10 |
| 2011 | 14 | 6 |
| 2012 | 8 | 4 |
| 2013 | 6 | 5 |
| 2014 | 10 | 2 |
| 2015 | 5 | 1 |
| 2016 | 4 | 3 |
| 2017 | 4 | 3 |
| 2018 | 1 | 2 |
| 2019 | 3 | 4 |
| 2020 | 2 | 1 |
| 2021 | 3 | 1 |
| 2022 | 3 | 2 |
| 2023 | 0 | 1 |
| 2024 | 2 | 2 |
| 2025 | 2 | 3 |
| 2026 | 2 | 2 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Using an on-premises telephony node during an outage7 Apr 2026US 12,598,257 B2Zoom Communications, Inc.
- Disaster plan implementation for a unified communications network17 Mar 2026US 12,581,014 B2Nuwave Communications, Inc.
- Method and system for communication control11 Mar 2025US 12,250,339 B2Granite Telecommunications, LLC
- Hybrid cloud PBX11 Feb 2025US 12,225,162 B2
- Telephony outage handling using an on-premises telephony node30 Jul 2024US 12,052,366 B2Zoom Video Communications, Inc.
- On-Premises Telephony Node Operation During an Outage2 Jul 2026US 2026/0189659 A1Zoom Communications, Inc.
- Disaster plan implementation for a unified communications network18 Jun 2026US 2026/0172505 A1Nuwave Communications, Inc.
- Hybrid Cloud PBX16 Oct 2025US 2025/0324000 A1
- Method and system for communication control26 Jun 2025US 2025/0211671 A1Granite Telecommunications, LLC
- Disaster plan implementation for a unified communications network3 Apr 2025US 2025/0112991 A1Nuwave Communications, Inc.
Most cited
By later US patents
- Method and system for providing redundancy in security systems served by a public switched telephone network252US 6,067,346 ALucent Technologies Inc. · 2000
- Redundant video alarm monitoring system249US 6,038,289 ASimplex Time Recorder Company · 2000
- Personalized assistance system and method249US 6,404,884 B1Grape Technology Group, Inc. · 2002
- Wireless backup telephone device216US 6,411,802 B1Bellsouth Intellectual Property Management Corporation · 2002
- Portable telephone in a security network210US 7,511,614 B2InGrid, Inc. · 2009