The SSM2163 provides eight audio inputs, each of which can be mixed under digital control to a stereo output. Each input channel can be attenuated up to 63 dB in 1 dB intervals, plus fully muted. Additionally, any input can be assigned to either or both outputs. A standard 3-wire serial interface is employed, plus a Data Out terminal to facilitate daisy chaining of multiple mixer ICs. No external components are required for normal operation.