Click free mute switch circuit for telephones

• US 6,690,793 B1
• Filed: 05/16/2000
• Issued: 02/10/2004
• Est. Priority Date: 05/17/1999
• Status: Expired due to Term

• Current Assignee: Mitel Networks Corporation
• Original Assignee: Mitel Corporation (Microchip Technology Incorporated)
• Inventors: King, Lawrence
• Primary Examiner(s): BARNIE, REXFORD N
• Application Number:
  US09/571,808
• Time in Patent Office: 1,365 Days
• Field of Search: 379/421, 379/419, 379/420.03, 379/387.01, 379/388.02, 379/424, 379/422, 379/390.01, 379/388.07, 379/388.05
• US Class Current: 379/421
• CPC Class Codes: H03G 3/348 Muting in response to a mechanical action or to power supply variations, e.g. during tuning; Click removal circuits
• CPC Class Codes: H04M 1/6016 in the receiver circuit

Abstract

A circuit for eliminating switching noise from a mute switch connected between a microphone capable of receiving and transmitting audio signals to a communication system, comprising, a switch state detector connected to the mute switch for generating an on signal in the event that the mute switch is open and generating an off signal in the event that the mute switch is closed, a codec circuit connected to the mute switch in parallel with the switch state detector for delaying the audio signals received by the microphone, and a CPU connected to the codec circuit for receiving the on signal and in response muting the audio signals and for receiving the off signal and in response transmitting the audio signals to the communication system.

Claims

1. A circuit for eliminating switching noise from a mute switch connected between a microphone capable of receiving and transmitting audio signals to a communication system, comprising:

a switch state detector connected to said mute switch for generating an on signal in the event that said mute switch is open and generating an off signal in the event that said mute switch is closed;

a delay circuit connected to said mute switch in parallel with said switch state detector for delaying said audio signals received by said microphone; and

a further circuit connected to said delay circuit for receiving said on signal and in response muting said audio signals and for receiving said off signal and in response transmitting said audio signals to said communication system.

2. The circuit of claim 1, wherein said further circuit is a digital circuit for transmitting silence code to said communication system in response to receiving said on signal.

3. The circuit of claim 2, wherein said digital circuit is a CPU.

4. The circuit of claim 1, wherein said delay circuit further comprises a codec for converting said audio signal from analog to digital format prior to transmission to said communication system.