Integrated Circuits Used 74LS191 Procedure Add IC 74LS191 into ICBase-1 (74LS191).Connect VCC Port to Pin-20 (VCC) of ICBase-1 (74LS191).Connect GND Port to Pin-4 (Input) of ICBase-1 (74LS191).Connect GND Port to Pin-8 (Ground) of ICBase-1 (74LS191).