Additional preview pages of the KK74ACT138 datasheet.
KK74ACT138 Product details
Features
three Chip Select inputs, two active-low and one active-high to facilitate the demultiplexing, cascading, and chipselecting functions. The demultiplexing function is accomplished by using the Address inputs to select the desired device output; one of the Chip Selects is used as a data input while the other Chip Selects are held in their active states.
TTL/NMOS Compatible Input Levels.
Outputs Directly Interface to CMOS, NMOS, and TTL.