H04M 19/023
By reversing the polarity of the current at the exchange
Official title: {by reversing the polarity of the current at the exchange}
H04M19/023 (By reversing the polarity of the current at the exchange) appears on 36 US grants and 1 published applications in this corpus.
Search patents in H04M- Granted patents
- 36
- Published applications
- 1
- Assignees
- 24
- Inventors
- 52
- Latest grant
- 31 Jan 2012
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
| 1977 | 0 | 0 |
| 1978 | 0 | 0 |
| 1979 | 3 | 0 |
| 1980 | 3 | 0 |
| 1981 | 0 | 0 |
| 1982 | 5 | 0 |
| 1983 | 3 | 0 |
| 1984 | 2 | 0 |
| 1985 | 2 | 0 |
| 1986 | 2 | 0 |
| 1987 | 3 | 0 |
| 1988 | 2 | 0 |
| 1989 | 2 | 0 |
| 1990 | 1 | 0 |
| 1991 | 2 | 0 |
| 1992 | 0 | 0 |
| 1993 | 1 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 1 | 0 |
| 1997 | 0 | 0 |
| 1998 | 1 | 0 |
| 1999 | 0 | 0 |
| 2000 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 0 |
| 2003 | 1 | 0 |
| 2004 | 0 | 0 |
| 2005 | 0 | 0 |
| 2006 | 0 | 0 |
| 2007 | 0 | 0 |
| 2008 | 0 | 1 |
| 2009 | 0 | 0 |
| 2010 | 0 | 0 |
| 2011 | 0 | 0 |
| 2012 | 1 | 0 |
By publication year. Applications have been published since 2001.
Recent patents
- Method and device for checking the function for inverting the polarity on a subscriber line comprising a plurality of wires31 Jan 2012US 8,107,615 B2Nokia Siemens Networks Oy
- Receiver and signal transmission system29 Jul 2003US 6,600,791 B1Matsushita Electric Industrial Co., Ltd.
- Leadframe for plastic-encapsulated semiconductor device, semiconductordevice using the same, and manufacturing method for the leadframe3 Mar 1998US 5,723,996 ASiemens Aktiengesellschaft
- Method of providing d.c. feed to a telephone line23 Apr 1996US 5,511,118 ANorthern Telecom Limited
- Polarity inverting circuit2 Mar 1993US 5,191,507 ANEC Corporation
Most cited
By later US patents
- Programmable ring signal generator63US 4,349,703 AInternational Telephone and Telegraph Corporation · 1982
- Method of providing d.c. feed to a telephone line58US 5,511,118 ANorthern Telecom Limited · 1996
- Electronic ringing signal generator53US 4,866,587 AAmerican Telephone and Telegraph Company, AT&T Bell Laboratories · 1989
- Line interface circuit34US 5,014,305 ANorthern Telecom Limited · 1991
- Programmable ring signal generator20US 4,656,659 AITT Corporation · 1987