H04Q 1/446
Using one signalling frequency
Official title: using one signalling frequency (H04Q1/46 takes precedence)
H04Q1/446 (Using one signalling frequency) appears on 43 US grants and 0 published applications in this corpus.
Search patents in H04Q- Granted patents
- 43
- Published applications
- 0
- Assignees
- 29
- Inventors
- 75
- Latest grant
- 10 Dec 2002
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 3 | 0 |
| 1977 | 5 | 0 |
| 1978 | 2 | 0 |
| 1979 | 0 | 0 |
| 1980 | 5 | 0 |
| 1981 | 1 | 0 |
| 1982 | 2 | 0 |
| 1983 | 2 | 0 |
| 1984 | 1 | 0 |
| 1985 | 4 | 0 |
| 1986 | 3 | 0 |
| 1987 | 2 | 0 |
| 1988 | 1 | 0 |
| 1989 | 2 | 0 |
| 1990 | 2 | 0 |
| 1991 | 1 | 0 |
| 1992 | 1 | 0 |
| 1993 | 1 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 0 | 0 |
| 1997 | 0 | 0 |
| 1998 | 0 | 0 |
| 1999 | 1 | 0 |
| 2000 | 0 | 0 |
| 2001 | 2 | 0 |
| 2002 | 2 | 0 |
By publication year. Applications have been published since 2001.
Subgroups
Granted patents
Recent patents
- System for ensuring calling party privacy in a call screening system10 Dec 2002US 6,493,432 B1Avaya Technology Corp.
- Line testing in a telecommunications network7 May 2002US 6,385,299 B1British Telecommunications Public Ltd.Co.
- Method and apparatus for electronic mail notification3 Apr 2001US 6,212,265 B1
- Line testing in a telecommunications network2 Jan 2001US 6,169,783 ABritish Telecommunicaitons public limited company
- Method and apparatus for defeating a predictive telemarketing system6 Jul 1999US 5,920,623 AVera-A-Fast
No published applications in this class yet.
Most cited
By later US patents
- Method and apparatus for electronic mail notification100US 6,212,265 B12001
- Signal detection and discrimination using waveform peak factor53US 4,696,031 AWang Laboratories, Inc. · 1987
- Call progress signal monitor and method for telephone systems50US 4,528,664 ANorthern Telecom Limited · 1985
- Signal analyzing system48US 5,070,526 AActive Voice Corporation · 1991
- Sampled signal detector28US 4,064,488 AMotorola, Inc. · 1977