Secondary Audio Program

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What Does Secondary Audio Program Mean?

Secondary Audio Program (SAP) is an auxiliary audio channel alternative to standard television (TV) stations or programs. SAP is transmitted via sub video carriers (for example, color TV) vs. audio carriers like FM radio. SAP is accessible via wireless, TV, videocassette recorder (VCR) or portable receiver.

Most TVs and VCRs manufactured after 1995 are SAP-enabled.

Techopedia Explains Secondary Audio Program

In 1984, the National Television System Committee (NTSC) incorporated SAP as part of its multichannel television sound (MTS) specification. NTSC and MTS specifications are applied in Canada, the United States, Mexico, Chile, Brazil, Argentina, the Philippines and Taiwan.

As of June 2009, the United States only uses MTS in analog TV because of the digital transition.

The following are SAP application examples:

  • (US) Public Broadcasting Service (PBS)
  • (US) Student radio stations: Used with limited FM signals
  • Canada’s Cable Public Affairs Channel (CPAC): Applies SAP in English and French

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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.