Most of the SYNC entertainment systems start to play as soon as you load media. With indexed devices, such as USB media players, SYNC first uploads the index, so it can take a few minutes for play to begin.
If you're already listening to an entertainment system, SYNC assumes your voice command is for that mode. To switch to a different entertainment system, you must name it to switch modes. For example, if Bluetooth Audio is streaming, and you want your USB media player, say "USB,” then give USB commands.34,48
"Track" refers to audio track and is usually the same as "song."