The Mixer uses eight DACs to control audio level and pan for four channels. Attenuation data for each DAC is latched from the PA bus group of U119 Programmable Peripheral Interface. The PB bus only accepts an input coding the number of pots. The PC bus outputs the pot and DAC addresses and strobes to U118 Vadc multiplexer and U117 DAC demultiplexer. The Mux sequentially samples the pots which are digitized by the ADC window comparator in the System Controller. U117 is actually operates as a decoder to use Vdac as the DAC select strobe. The DACs can be used in pan applications because their two outputs are complementary.