Integrated Circuits Used 74LS00 Procedure Add IC 74LS00 into ICBase-1 (74LS00).Connect Pin-19 (Input) of ICBase-1 (74LS00) to Pin-7 (Input & Output) of ICBase-2.Connect Pin-7 (Input & Output) of ICBase-2 to Pin-16 (Input) of ICBase-1 (74LS00).