An interface circuit for interconnecting the fixed controls of a vehicle to a replacement stereo. The interface circuit is capable of receiving control signals from fixed controls, such as steering wheel controls, backseat controls, handlebar controls, and the like, and then transmitting corresponding control signals to a replacement stereo. In one embodiment, the output signals from the interface circuit are comprised of wireless signals, such as IR signals. In another embodiment, the interface device is programmable such that the interface device can be programmed to emit signals corresponding to the same signals that would be emitted from a handheld remote control sold in conjunction with an after-market stereo receiver.