The definition of SAP - (Supplementary Audio Program, Second Audio Program Switch).

Electronic program guides, art, cultural and media studies, digital television, enhanced TV, games and betting, interactive television, interactive, ITV advertising, digital storytelling, satellite, broadcasting, ecommerce, T-commerce, t commerce, terrestrial broadcasting, microwave, nab, atsc, dvb, mph-dvb, xml, open standards, opencable, server, Server, servers, headend, head-end, interface, cofdm, TV guide, internet at TV, networking (technical and social), new genres, interaction design, new standards, personalized TV, design and media, the interactive viewer/user, video-on-demand, Media Theory, T-commerce, Strong CE Spending Family Budget can Afford it Multicasting Better Picture Quality Wider Screen Improved Surround Sound More Programming Choices Electronic Program Guides (EPGs) Simpler Remote Controls Interactive Services Enhanced Set-top Boxes Available Content Content Archives Movie Libraries Repackaged News E Subsidies Other Subsidies Asset Protection Broken Business Models Increased Ad Revenue Potential Cheaper and more Targeted TV Ads Mass Customization Experienced Call Centers Lower Operating Costs New Revenue Sources Distance Learning Broadband Competition Semiconductor Competition Availability of High-definition TV Sets Separation of Function Video Format Conversion Home Networks The Master Set-top Box Enhanced-TV Market Inhibitors Inadequate Management Systems Expensive Infrastructure Upgrades Dearth of Compelling Content Risky New Business Models High Consumer Cost of HDTV Price vs. Quality Large Screens Take Up Space Installed Base of Legacy TVs High Consumer Cost of Set-top Boxes Installation Hassles Long-Term Commitments FCC Deadlines Won’t HoldLack of Market Demand Personal Privacy Established Usage Patterns No Guarantee of Service Quality Inadequate Home Wiring.