Telephony, network and cable television, music-oriented FM radio, AM talk radio, even satellite radio and television all see their foundations crumbling under the onslaught of the Internet.
Once the device syncs with a navigation unit, the audio is then piped to the Mainnav via a 3.5-millimeter audio cable, and if you're actually in one of those remote areas where an FM transmitter can broadcast something other than fuzz, you're good to go.