SAP stands for secondary audio programming. It is used as an alternative to standard audio programming, allowing for a signal to be broadcast in another language or, sometimes, an audio broadcast unrelated to what appears on the television screen.
SAP service is used for people with visual disabilities. The alternate audio broadcasts a description of the images on the screen. It is also used for translation. Shows typically broadcast in English can be heard in Spanish or other languages via SAP. Occasionally, SAP programming is used to broadcast weather updates or news.
Most television sets with stereo sound manufactured after 1995 have SAP options available through audio setup. It can also be accessed through a stereo VCR or special receiver.
In 2002, the United States' Federal Communications Commission (FCC) required that local ABC, CBS, NBC and Fox networks provide a minimum of 4 hours of SAP programming for the visually impaired each week. The FCC eventually hopes to enforce the same requirements to satellite and cable TV stations.
SAP is often used for Spanish broadcasts, thus the acronym is often misinterpreted to mean "Spanish audio programming" instead of secondary audio programming.