A vehicle system interface comprises an antenna configured to receive a digital radio signal, a digital radio receiver circuit configured to receive the digital radio signal from the antenna and to obtain digital audio data from the digital radio signal, an FM modulator and transmitter circuit, and a microprocessor in operable communication with the digital radio receiver circuit and the FM modulator and transmitter circuit. The microprocessor is configured to generate a first message requesting a series of FM radio signal levels corresponding to a series of FM radio frequencies being received by an FM radio receiver. The microprocessor is configured to send the first message through an electrical connector to a control system in operable communication with the FM radio receiver. The microprocessor is configured to receive a second message from the control system through the electrical connector indicating the series of FM radio signal levels. The microprocessor is configured to select a suitable FM radio frequency from the series of FM radio frequencies based upon the corresponding series of FM radio signal levels. The microprocessor is configured to generate a third message instructing the control system to tune the FM radio receiver to the suitable FM radio frequency. The microprocessor is configured to send the third message through the electrical connector to the control system. The microprocessor is configured to transmit the digital audio data from the digital radio receiver circuit to the FM modulator and transmitter circuit. The microprocessor is configured to induce the FM modulator and transmitter circuit to broadcast the digital audio data in an FM radio signal over the suitable FM radio frequency.