Setting Pin Swaps Use Set Pin Swap to define a swap class for a terminal. Swapping information is used in the PCB layout application for length minimization and routing optimization. The swap class is assigned by a numeric value. The number for classes is 0, if the pin is not to be swapped under any circumstances, and 1 through 99. A pin can be swapped with any other pin within the gate that has the same swap class number.