"perfect" logic level shifting

GoingForGold - The circuits should work. 10k seems a little high, but it's probably a good place to start. If you want it really bullet proof use a level shifter or opto-isolators.

Chagrin - Opto-isolators are available in DIP as are CD4504, CD40109, MC14504 or LTC1045 level shifters, but if you use the circuits the OP referenced, they don't need IC's at all.

Steve T