Exchange line circuits

Industry

CPC
H04M9/006

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Parent Industries

HELECTRICITY H04Electric communication H04MTELEPHONIC COMMUNICATION H04M9/00Interconnection arrangements not involving centralised switching

Current Industry

H04M9/006Exchange line circuits

Industries

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Patents Grantslast 30 patents

Information Patent Grant
Circuit and method for reducing common mode interference in telepho...
- Patent number 5,694,460
- Issue date Dec 2, 1997
- Lucent Technologies Inc.
- Brian Albert Wittman
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key telephone interface
- Patent number 5,097,501
- Issue date Mar 17, 1992
- AT&T Bell Laboratories
- Walter G. Kutzavitch
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Control and interface apparatus for telephone systems
- Patent number 5,048,080
- Issue date Sep 10, 1991
- AT&T Bell Laboratories
- John F. Bell
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key telephone system
- Patent number 4,935,957
- Issue date Jun 19, 1990
- Nitsuko Limited
- Kinzi Tanaka
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Office line interface circuits
- Patent number 4,856,058
- Issue date Aug 8, 1989
- Kabushiki Kaisha Toshiba
- Yasuji Sato
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Music on hold for key systems
- Patent number 4,588,865
- Issue date May 13, 1986
- Vodavi Technology Corporation
- Alfred M. Hestad
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Telephone lines status sensor
- Patent number 4,446,338
- Issue date May 1, 1984
- Northern Telecom Limited
- Reinhard W. Rosch
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key telephone line circuit with improved hold circuit
- Patent number 4,445,004
- Issue date Apr 24, 1984
- Northern Telecom Limited
- Paul Y. Ho
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Line circuit for multiple line telephone
- Patent number 4,394,544
- Issue date Jul 19, 1983
- GTE Automatic Electric Labs Inc.
- Daniel De Leon
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Microcomputer controlled key telephone line circuit
- Patent number 4,382,163
- Issue date May 3, 1983
- GTE Automatic Electric Labs Inc.
- Thomas E. White
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Interface circuit for telephone line to equipment signal coupling
- Patent number 4,323,734
- Issue date Apr 6, 1982
- Crest Industries, Inc.
- Gene A. Kimzey
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key telephone line shunt detector circuit
- Patent number 4,323,735
- Issue date Apr 6, 1982
- Bell Telephone Laboratories, Inc.
- Gerry C. Balzer
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Line/interface circuit for key telephone systems
- Patent number 4,207,439
- Issue date Jun 10, 1980
- International Telephone & Telegraph Corporation
- Bruce R. Saxon
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key system protective apparatus
- Patent number 4,194,093
- Issue date Mar 18, 1980
- International Telephone & Telegraph Corporation
- Orland L. Davis
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Telephone system open switching interval protection circuit
- Patent number 4,158,755
- Issue date Jun 19, 1979
- Bell Telephone Laboratories, Incorporated
- Phillip P. Daniele
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key telephone unit protective coupler
- Patent number 4,145,579
- Issue date Mar 20, 1979
- Bell Telephone Laboratories, Incorporated
- Ronald J. Angner
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key telephone system optically coupled protective coupler
- Patent number 4,132,870
- Issue date Jan 2, 1979
- Bell Telephone Laboratories, Incorporated
- Chao Kai Liu
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Line circuit for key telephone systems
- Patent number 4,101,740
- Issue date Jul 18, 1978
- International Standard Electric Corporation
- John Anthony Barsellotti
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Line circuit for key telephone systems
- Patent number 4,101,741
- Issue date Jul 18, 1978
- International Standard Electric Corporation
- George Kunstatter
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key telephone system line circuit
- Patent number 4,093,830
- Issue date Jun 6, 1978
- Vortex Design Ltd.
- Jeffrey Pappas
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Line circuit for key telephone systems
- Patent number 4,071,712
- Issue date Jan 31, 1978
- International Standard Electric Corporation
- John Anthony Barsellotti
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Line circuit for key telephone systems
- Patent number 4,064,373
- Issue date Dec 20, 1977
- International Standard Electric Corporation
- Edouard Pinede
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Logic control for electronic key telephone line circuit
- Patent number 4,057,693
- Issue date Nov 8, 1977
- Bell Telephone Laboratories, Incorporated
- Ronald Joseph Angner
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key telephone line circuit tone-on-hold arrangement
- Patent number 4,056,695
- Issue date Nov 1, 1977
- Bell Telephone Laboratories, Incorporated
- Ronald Joseph Angner
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key telephone off-premises line circuit
- Patent number 4,039,762
- Issue date Aug 2, 1977
- Bell Telephone Laboratories, Incorporated
- Albert Edward Donkin
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key telephone communication path interface
- Patent number 4,039,763
- Issue date Aug 2, 1977
- Bell Telephone Laboratories, Incorporated
- Ronald Joseph Angner
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Key telephone system
- Patent number 4,024,353
- Issue date May 17, 1977
- Iwatsu Electric Co., Ltd.
- Tokuhisa Hijikata
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Line circuit for use with a key telephone system
- Patent number 4,004,106
- Issue date Jan 18, 1977
- Akzona Incorporated
- Gerald J. Yachabach
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Security line card circuit
- Patent number 3,997,737
- Issue date Dec 14, 1976
- San/Bar Corporation
- Arthur Gene Watkins
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Line card circuit
- Patent number 3,965,308
- Issue date Jun 22, 1976
- San/Bar Corporation
- Wilson Franklin Jones
- H04 - ELECTRIC COMMUNICATION TECHNIQUE

Exchange line circuits

Industry

Parent Industries

Current Industry

Patents Grantslast 30 patents

Circuit and method for reducing common mode interference in telepho...

Key telephone interface

Control and interface apparatus for telephone systems

Key telephone system

Office line interface circuits

Music on hold for key systems

Telephone lines status sensor

Key telephone line circuit with improved hold circuit

Line circuit for multiple line telephone

Microcomputer controlled key telephone line circuit

Interface circuit for telephone line to equipment signal coupling

Key telephone line shunt detector circuit

Line/interface circuit for key telephone systems

Key system protective apparatus

Telephone system open switching interval protection circuit

Key telephone unit protective coupler

Key telephone system optically coupled protective coupler

Line circuit for key telephone systems

Line circuit for key telephone systems

Key telephone system line circuit

Line circuit for key telephone systems

Line circuit for key telephone systems

Logic control for electronic key telephone line circuit

Key telephone line circuit tone-on-hold arrangement

Key telephone off-premises line circuit

Key telephone communication path interface

Key telephone system

Line circuit for use with a key telephone system

Security line card circuit

Line card circuit

Patents Applicationslast 30 patents