Circuitry for controlling mode selection of a CD/DVD reader is described. In one embodiment, the CD/DVD reader has a first device having at least one analog output, a second device having at least one digital input and at least one analog input, and an interface circuit coupling the analog output of the first device to the digital input and the analog input in the second device. The interface circuit includes a circuitry to use a single control signal from the analog output of the first device to control the digital input and the analog input in the second device. Other embodiments are also described.