The 'AC257, 'ACT257 and CD74ACT258 are quad 2-input multiplexers with three-state outputs that utilize Advanced CMOS Logic technology. Each of these devices selects four bits of data from two sources under the control of a common Select input (S). The Output Enable (OE) is active LOW. When OE is HIGH, all of the outputs (Y or Y) are in the highimpedance state regardless of all other input conditions.