This is a four channel logic jumbler. The most common way to use this would be to plug 4 gates into the 4 inputs and derive logical combinations on the outputs. However, the inputs accept any signal (audio, LFOs, envelopes, you name it) and will decide that they are active if their value is above 1 volt.
On top of the logic jumbling, the four output channels are used to create a 4-bit stepped output at the STEP jack. This output also appears at the SLEW jack, but with a variable amount of smoothing set by the SLEW control.
Finally, if a cable is plugged into the SAMPLE input, the four output gates will only change upon the reception of a trigger here. This is useful for enforcing a more rigid tempo upon the outputs.
The big switch on the top selects the active logic mode: OR, AND, XOR, NOR, XNOR