Precision adder (mixer) and buffer for control voltages. Precision means that the amplification of the inputs without attenuators is exactly 1.00. When playing VCOs this means a correct tracking of 1V/oct.
The A-185-2 allows you to send up to four control voltages simultaneously (eg. sequencer and keyboard for transposing sequences) to one or more VCOs. There are three buffered outputs and an inverted one.
You can also use the A-185-2 as a octave switch because the rocker switches produce a 1V offset voltage when nothing is plugged.