Complex sentence: The EL-8's logic circuits use the same four Rockwell-manufactured LSI ("large-scale integration") integrated circuits that are used in the QT-8D and QT-8B.
Split into simpler sentences: The EL-8's electronics are contained in four Rockwell-manufactured LSI ("large-scale integration") integrated circuits. These same circuits had already been used in the QT-8D and QT-8B.