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Detection and bypass of tandem vocoding using detection codes

  • US 5,956,673 A
  • Filed: 01/25/1995
  • Issued: 09/21/1999
  • Est. Priority Date: 01/25/1995
  • Status: Expired due to Term
First Claim
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1. A method for avoiding tandem vocoding in a communications system wherein speech data vocoded according to a predetermined vocoding format is transmitted over a pulse code modulated (PCM) system having a PCM communications link, comprising the steps of:

  • converting, at a first vocoder, vocoded data from a first remote source into a first PCM encoded signal for transmission over said PCM communications link;

    including in said first PCM encoded signal a transmitted detection code;

    receiving at said first vocoder a second PCM encoded signal over said PCM communications link;

    converting, at said first vocoder, said second PCM encoded signal into vocoded data for transmission to said first remote source;

    monitoring at said first vocoder said second PCM encoded signal to discern whether said second PCM encoded signal comprises a received detection code;

    including directly in said first PCM encoded signal said vocoded data from said first remote source if said second PCM encoded signal comprises said received detection code;

    monitoring at said first vocoder said second PCM encoded signal to discern whether said second PCM encoded signal comprises vocoded data from a second remote source; and

    passing by said first vocoder said vocoded data from said second remote source as said vocoded data for transmission to said first remote source if said second PCM encoded signal comprises vocoded data from said second remote source.

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