This new 12-Volt Bluetooth receiver is designed so that you can play the stereo audio output of a Smart phone or tablet in any automotive audio system that has an Auxiliary input. There are only two wires for power and one for the audio signal. Simply connect the RED wire on the N-401 to +12 Volts DC accessory and connect the BLACK wire to chassis ground. Feed the 3.5mm stereo jack to the Auxiliary input on your vehicle’s audio system (OEM or Aftermarket). Link-up is automatic and an automatic alert tone will be heard as soon as the car’s accessories are active. You are now ready to transmit audio from your Smart phone into the N-401. Turn on your Smart phone’s Bluetooth and start listening through your car’s audio system. The N-401 turns your car’s sound system into a Bluetooth enhanced audio system. Incredible quality – far superior to FM Modulators.