

Instead of transmitting via the FM band, a signal modulated with the output from your iPod is inserted via the hard-wired connection.

FM modulators are similar to FM transmitters, but they are designed to be hard-wired in between your head unit and car antenna.A physical wire connects the FM transmitter to the headphone jack in your iPod, and then the device transmits your music to your head unit via the FM band. That means these adapters are useful if your head unit doesn’t have a tape deck or an auxiliary input. FM transmitters can be used to connect any type of iPod, iPhone, and really any other type of MP3 player, to any head unit that has an FM radio.You use this type of adapter by inserting the unit into your tape deck and then plugging it into your iPod’s headphone jack. The sound quality of a cassette tape adapter will depend on the condition of the tape deck, the build quality of the adapter itself, and other factors, but they aren’t prone to outside interference. Cassette tape adapters are designed for older head units that have cassette decks but no built-in auxiliary inputs.
