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Class Information
Number: 379/282
Name: Telephonic communications > Centralized switching system > Switching controlled in response to called station addressing signal > Having shared or common switching control > Including registering or storing device for call address signal > Voice frequency receiver
Description: Subject matter which is selectively responsive to audio frequency signalling tones.
Sub-classes under this class:
Patents under this class:
| Patent Number |
Title Of Patent |
Date Issued |
| 7003093 |
Tone detection for integrated telecommunications processing |
Feb. 21, 2006 |
| 6850616 |
Frequency error detection methods and systems using the same |
Feb. 1, 2005 |
| 6839429 |
Spectral optimization for communication under a peak frequency-domain power constraint |
Jan. 4, 2005 |
| 6771767 |
Signal detector with coefficient swapping transform unit |
Aug. 3, 2004 |
| 6580792 |
Signal detector with automatic gain control |
Jun. 17, 2003 |
| 6493441 |
Method of controlling telecommunications signalling |
Dec. 10, 2002 |
| 6484139 |
Voice frequency-band encoder having separate quantizing units for voice and non-voice encoding |
Nov. 19, 2002 |
| 6381330 |
False tone detect suppression using multiple frame sweeping harmonic analysis |
Apr. 30, 2002 |
| 6314175 |
System and method for redirecting control of in-band signaling |
Nov. 6, 2001 |
| 6301355 |
Method and apparatus for analyzing dual tone multi-frequency (DTMF) signals on a private branch exchange (PBX) switch |
Oct. 9, 2001 |
| 6229889 |
Robust signaling tone frequency measurement |
May. 8, 2001 |
| 5867568 |
Coverage of redirected calls |
Feb. 2, 1999 |
| 5850437 |
Transmission system with improved tone detection |
Dec. 15, 1998 |
| 5850438 |
Transmission system with improved tone detection |
Dec. 15, 1998 |
| 5809133 |
DTMF detector system and method which performs frequency domain energy calculations with improved performance |
Sep. 15, 1998 |
| 5729602 |
Programmable multi-tone voice message starting system |
Mar. 17, 1998 |
| 5694466 |
DTMF detector system and method which performs improved twist computation and thresholding |
Dec. 2, 1997 |
| 5692040 |
Method of and apparatus for exchanging compatible universal identification telephone protocols over a public switched telephone network |
Nov. 25, 1997 |
| 5675632 |
Telephone exchange network using telephone exchanges with speech recognition |
Oct. 7, 1997 |
| 5638436 |
Voice detection |
Jun. 10, 1997 |
| 5619564 |
Tone detector with improved performance in the presence of speech |
Apr. 8, 1997 |
| 5619565 |
Voice activity detection method and apparatus using the same |
Apr. 8, 1997 |
| 5588053 |
DTMF detector system and method which performs static and dynamic thresholding |
Dec. 24, 1996 |
| 5583934 |
DC level control for an electronic telephone line card |
Dec. 10, 1996 |
| 5535271 |
Apparatus and method for dual tone multifrequency signal detection |
Jul. 9, 1996 |
| 5533118 |
Voice activity detection method and apparatus using the same |
Jul. 2, 1996 |
| 5519774 |
Method and system for detecting at a selected station an alerting signal in the presence of speech |
May. 21, 1996 |
| 5495526 |
Tone-detection method for detecting at least one tone in a dual-tone multifrequency signal, call-progress method using the same |
Feb. 27, 1996 |
| 5459781 |
Selectively activated dual tone multi-frequency detector |
Oct. 17, 1995 |
| 5426696 |
Method of improving receiver sensitivity and speech immunity with DTMF-reception |
Jun. 20, 1995 |
| 5416836 |
Disconnect signalling detection arrangement |
May. 16, 1995 |
| 5406621 |
Telephone tone analysis system |
Apr. 11, 1995 |
| 5392348 |
DTMF detection having sample rate decimation and adaptive tone detection |
Feb. 21, 1995 |
| 5333191 |
Detection of multifrequency tone signals |
Jul. 26, 1994 |
| 5321745 |
Adaptive efficient single/dual tone decoder apparatus and method for identifying call-progression signals |
Jun. 14, 1994 |
| 4896346 |
Password controlled switching system |
Jan. 23, 1990 |
| 4829562 |
Receiver for detecting different fixed frequency signals on a telephone trunkline |
May. 9, 1989 |
| 4763350 |
Facility for detecting and converting dial information and control information for service features of a telephone switching system |
Aug. 9, 1988 |
| 4621358 |
Remote switch for telephony switching system |
Nov. 4, 1986 |
| 4161630 |
Circuit arrangement for use in telephone systems |
Jul. 17, 1979 |
| 4076965 |
Universal receiver/sender |
Feb. 28, 1978 |
| 4017695 |
Customer operated gain control circuit |
Apr. 12, 1977 |
| 4004105 |
Multifrequency signal receiver for use in telephone signaling systems or the like |
Jan. 18, 1977 |
| 3993875 |
Tone receiver |
Nov. 23, 1976 |
| 3971899 |
Signalling device for key telephone systems |
Jul. 27, 1976 |
| 3971897 |
Circuit arrangement for a selective signal receiver, particularly for use in telephone systems |
Jul. 27, 1976 |
| 3949177 |
Method for frequency-recognition in selective signal receivers for use in telecommunication, particularly telephone systems |
Apr. 6, 1976 |
| 3941938 |
Time shared TCMF and MF decoder |
Mar. 2, 1976 |
| 3937899 |
Tone detector using spectrum parameter estimation |
Feb. 10, 1976 |
| 3935395 |
Selective signal receiver for use in telecommunication systems |
Jan. 27, 1976 |
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