H04Q 1/38
Using combinations of direct currents of different amplitudes or polarities over line
Official title: using combinations of direct currents of different amplitudes or polarities over line conductors or combination of line conductors
H04Q1/38 (Using combinations of direct currents of different amplitudes or polarities over line) appears on 29 US grants and 2 published applications in this corpus.
Search patents in H04Q- Granted patents
- 29
- Published applications
- 2
- Assignees
- 25
- Inventors
- 51
- Latest grant
- 20 May 2025
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 0 | 0 |
| 1978 | 3 | 0 |
| 1979 | 1 | 0 |
| 1980 | 0 | 0 |
| 1981 | 2 | 0 |
| 1982 | 2 | 0 |
| 1983 | 0 | 0 |
| 1984 | 3 | 0 |
| 1985 | 4 | 0 |
| 1986 | 2 | 0 |
| 1987 | 2 | 0 |
| 1988 | 1 | 0 |
| 1989 | 4 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 0 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 0 | 0 |
| 1999 | 0 | 0 |
| 2000 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 0 |
| 2003 | 0 | 0 |
| 2004 | 0 | 0 |
| 2005 | 0 | 0 |
| 2006 | 0 | 0 |
| 2007 | 0 | 0 |
| 2008 | 0 | 0 |
| 2009 | 0 | 0 |
| 2010 | 0 | 0 |
| 2011 | 0 | 0 |
| 2012 | 0 | 0 |
| 2013 | 0 | 0 |
| 2014 | 0 | 0 |
| 2015 | 0 | 0 |
| 2016 | 0 | 0 |
| 2017 | 0 | 0 |
| 2018 | 0 | 1 |
| 2019 | 0 | 0 |
| 2020 | 1 | 0 |
| 2021 | 0 | 0 |
| 2022 | 0 | 0 |
| 2023 | 0 | 1 |
| 2024 | 0 | 0 |
| 2025 | 1 | 0 |
By publication year. Applications have been published since 2001.
Recent patents
- Antenna and electronic device including same20 May 2025US 12,308,509 B2Samsung Electronics Co., Ltd.
- Antenna arrangement on a circuit board25 Feb 2020US 10,573,970 B2Sony Corporation
- Paystation transmitter ground detect circuitry11 Apr 1989US 4,821,313 APalco Telecom Inc.
- DX circuit21 Mar 1989US 4,815,124 ATellabs Oy
- Telephone line switch21 Mar 1989US 4,815,126 AAlcatel
Most cited
By later US patents
- Subscriber line interface circuit62US 4,540,854 AMitel Corporation · 1985
- Ground start circuit13US 4,796,290 AKeptel, Inc. · 1989
- Loop current detector with threshold setting impedance12US 4,454,477 AAT&T Bell Laboratories · 1984
- Telephone line switch11US 4,815,126 AAlcatel · 1989
- Current detection circuit arrangement for an automatic telephone exchange8US 4,319,092 AU. S. Philips Corporation · 1982