RCA DTV307 User Manual page 50

Icon in the Channel Banner
You will find an audio language icon in the channel banner.
Audio language icon
If the icon is highlighted while watching a digital (ATSC) or DIRECTV
channel, two or more audio languages are available. Selecting the
icon repeatedly scrolls through and plays the options.
If the icon is highlighted when watching an analog (NTSC) TV
channel, a Second Audio Program (SAP) is available. Selecting the
icon will play the SAP for the current channel until the channel is
changed.
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