An accessory for a portable electronic device, such as a digital music player, includes a set of device controls for controlling the portable electronic device. The accessory includes a microprocessor and a memory that contains function codes corresponding to the functions selected by the controls. In response to user manipulation of the controls, the accessory sends the function codes to the portable electronic device that cause the device to perform the requested function. Preferably, the accessory is a charger is adapted to be inserted into for a 12-volt car auxiliary power outlet and has the controls on the protruding face of the charger body. The accessory may also include an FM transmitter for transmitting an audio signal received from the portable electronic device to the car stereo.